DEEP HOLE DRILLING INSERTS,LATHE MACHINE CUTTING TOOLS,CARBIDE INSERTS

The shop is divided into areas for EDM and conventional machining. Equipment includes six wire EDM machines and seven vertical machining centers.

Making parts that have narrow requirements for both tolerances and delivery times affects the choice of inspection technology as much as it shapes machining capabilities. A high-end CMM is one of the shop's most Cermet Inserts significant investments.

Communication is emphasized as a way to avoid costly errors. Grease boards at each machine encourage operators to share information. Work instructions for each job are very detailed.

The square "base" of this unfinished part is built-in workholding. It was machined as part of the EDM cycle specifically so it could be used for clamping and locating during the machining center cycle. As soon as the part is complete, the base will be machined away.

Using EDM to machine the tiny holes in this part was a challenge, because the part's copper and molybdenum layers tended to separate. The shop overcame this challenge through experimentation.

Using EDM to machine the tiny holes in this part was a challenge, because the part's copper and molybdenum layers tended to separate. The shop overcame this challenge through experimentation.

Communication TNGG Insert is emphasized as a way to avoid costly errors. Grease boards at each machine encourage operators to share information. Work instructions for each job are very detailed.

Communication is emphasized as a way to avoid costly errors. Grease boards at each machine encourage operators to share information. Work instructions for each job are very detailed.

The shop is divided into areas for EDM and conventional machining. Equipment includes six wire EDM machines and seven vertical machining centers.

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Colorado Aerospace has been experimenting from the beginning. The search for more effective machining techniques occupied the Boulder, Colorado, contract shop for several months before the shop officially opened for business in 1999. The effort also consumed much of the shop's available cash, depleting a Small Business Administration loan before the company had even opened its doors.

But the time and money were spent fruitfully, says company president Jack Cahn. The experimentation involved the shop's first CNC machine tool, a five-axis wire EDM machine. The shop used this machine to produce sample parts impressive enough in terms of geometry, cycle time and precision to win the attention of potential customers who have the most challenging work up for bid—a list that includes OEMs in the medical and communications industries and suppliers to NASA. Focusing the attention of his company on this high-end work is the best way Mr. Cahn sees to make his shop viable and successful in a market where more traditional contract machining businesses increasingly are struggling. And experimentation—both to refine existing techniques and to find ways to machine parts that befuddle other shops—continues to be an important factor in winning this high-end work.

For the work that Colorado Aerospace pursues, Mr. Cahn has certain specific criteria in mind. The ideal jobs have all of these characteristics in common: (1) narrow tolerances, (2) compressed lead time, (3) exotic materials that are difficult to machine and (4) the need for traceability through a detailed paper trail. This combination has the advantage of sharply limiting the field of potential competitors.

One noteworthy success for the shop—and an example of work that meets all four requirements—is a variety of parts that the shop is producing for the Mars Exploration Rover project. Two rovers scheduled for launch in 2003 (and arrival on Mars in 2004) will have parts from Colorado Aerospace all over them, as the shop is a machining contractor to four different NASA suppliers at work on this project.

The shop currently has six wire EDM machines and seven vertical machining centers. But to Mr. Cahn, buying machine tools is probably the most straightforward part of equipping the shop. He buys EDM machines from Mitsubishi EDM (Wood Dale, Illinois) because of the service and technical support he has received from this company, and he buys Matsuura machining centers from Methods Machine Tools (Sudbury, Massachusetts) because of the precision of these machines. More difficult than buying machines is using them effectively, and this effectiveness is determined by the overall process that's put in place around them.

Process And People

To machine parts that are simultaneously challenging in terms of accuracy, machinability and delivery time, the shop relies on a production process in which each of these elements figures prominently.

• Measurement capability. Delivering tight-tolerance parts within short lead times calls for not only fast precision machining but also fast precision measurement. The shop's "Universal Precision Measuring Center" from Carl Zeiss (Minneapolis, Minnesota) is a high speed scanning CMM measuring size, form and feature locations in a single setup, using a measuring increment as small as 0.00015 inch between points.

Another measuring instrument lets the shop increase its income with an ongoing side business. The linear measurement system from SIP (Hebron, Kentucky) that the shop uses to calibrate its gages also lets the shop provide a gage calibration service to other shops.

• Workholding by design. Most of the shop's parts involve both wire EDM and machining center work. For these parts, the shop looks for ways to use wire EDM to allow the machining center work to be performed more efficiently. Extra stock left on the part after EDM can serve as a convenient clamping and locating surface for milling or drilling.

This extra stock most often takes the form of a squared-off base that connects to the part like the pedestal of a trophy. (See photo below, at right.) In the absence of a base such as this, a part that requires two holes to be drilled 90 degrees apart might require two time-consuming setups on the machining center, or else one such setup in conjunction with an indexer. The shop's answer to this is to produce the base as part of the EDM cycle, with the base's orientation chosen so that the flats are square with the desired hole positions. The operator at the machining center can then avoid a lengthy setup by simply clamping on these faces.

In fact, the base doesn't have to be square. An octagonal base could accommodate milled or drilled features located 45 degrees apart, for example. Whatever the shape, the base is cut away once the machining center work is done.

• Respect for grinding. Surface grinding is not considered a mundane part of the process at this shop, but instead it's seen as a critical first step that can let the rest of the process run smoothly. Before they become the workpieces set up at other machine tools, blocks are machined to precise tolerances. The step is taken as a precaution against compounding error, which is a danger whenever an oversize or out-of-square part is to be rotated in the move from one setup to the next. Materials are so expensive and lead times are so short for this shop, it's in the shop's interest to machine away as much potential for error as it can at the outset of the process.

The sensitive measuring equipment (particularly the CMM) allows the shop to detect very small errors in the ground blocks, and stationing a skilled machinist at the surface grinder ensures that small errors can be removed. For example, a typical job had the machinist grinding 90 millionths from a block to make it square within 0.00050 inch before it was sent on for wire EDM.

• Communication. Mr. Cahn would cite this as the most important part of the process. Communication between employees who are working on the same job, or on the same machine, is even more effective than surface grinding for avoiding potential errors.

The technology used to accomplish this communication is inexpensive. A grease board is attached to every machine so the operator can leave behind whatever information might be useful for the operator using the machine next. And instead of using shop management software to route and track each job, the shop uses a spreadsheet created in Microsoft Word that offers the freedom to include detailed work instructions for every operation the job requires—instructions that an employee of almost any other shop would find surprisingly thorough.

People make this system work, says Mr. Cahn. Prospective shopfloor employees are evaluated specifically on their openness and ability to communicate effectively. And the programmer who writes most of the shop's work instructions is a person whose conscientious attention to detail is the driving force behind this system.

Ready Fire Aim

It may seem like a contradiction that experimentation, with all of its unpredictability, is a routine part of a machining process that is so carefully managed and controlled. But to Colorado Aerospace there is no contradiction, because the shop sees experimentation as something that can also be managed and controlled. For a particular machining challenge, the shop begins with the assumption that a workable solution to that challenge will be found, then devises the plan for arriving at that solution. Instead of ready-aim-fire, the approach is ready-fire-aim.

For example, the timetable for overcoming a particular machining problem within a small window of days might go something like this:

Day one. Create a list of hypotheses ("blue sky" ideas) for why the problem may be occurring. Day two. Consider the merits of each of the hypotheses and rank them in order of likelihood. Day three. Devise experiments for testing each one. Days four and five. Run the experiments. Day six. Incorporate the findings into the process for machining the part.

If it sounds cavalier that the shop takes on machining challenges fully expecting to find the solution within a matter of days, it shouldn't. The shop undertakes this experimentation at considerable expense. Each of the steps above requires the undivided attention of multiple employees, and some of these steps require time on the machines. These are resources that the shop might otherwise employ to run established parts using processes that have already been proven.

An example of a machining challenge overcome in this way involved 0.050-inch diameter holes machined via EDM in 0.010-inch-thick workpieces made of copper layered over molybdenum. Starter holes 0.032 inch in diameter were drilled prior to EDM. During the process of enlarging these holes, the parts often showed delamination—an unacceptable separating of the layers.

Testing various hypotheses to determine what might be causing this effect revealed a clear trend: An EDM machine known to run hotter invariably produced more delamination than a machine that was cooler-burning. This suggested that the effect was temperature-related. Heat propagating from the spark gap was causing the delamination. The shop needed to find a way to control this heat even better than the cooler-burning machine was able to control it. The solution at which the shop arrived was to take extra measures to chill the deionized water, running these parts within water that has a much lower temperature than what is typical for wire EDM.

Every such problem that the shop solves represents one more step forward in the shop's capabilities, and—at least temporarily—one more advantage over competitors. The shop can keep moving its expertise forward in this way indefinitely.

But to do so, Mr. Cahn realizes that the shop may have to clear away artificial boundaries that limit what the company can do. How can the shop keep on expanding its services to the customers for high-end work? One way may be to expand the range of its services to include more than just machining. What exactly that additional level of service would comprise is not at all clear to Mr. Cahn, but the question is one that he and the rest of the shop's management are wrestling with right now.

Today Colorado Aerospace is a contract machine shop, but Mr. Cahn doesn't want a simple niche or definition to limit the company if it might be something more than this. Growing his own business may be another example of a challenge undertaken with the assumption that a solution can be found.

The Carbide Inserts Blog: https://billkyle.exblog.jp/

The shop floor at Rekluse is lined with VersaBuilt's Automation Systems. Rekluse has 26 total VersaBuilt systems on its floor. Photo Credit: VersaBuilt

About a decade ago, Rekluse had a problem. The Idaho-based maker of aftermarket motorcycle clutches deals with cyclical business. During the summer months, bikers are out riding, and they use the winter months to work on their bikes, making whatever improvements they can before the days get longer and the warm weather invites them to ride again.

This leads to Rekluse’s business doubling during the winter when people are ordering parts to work on their motorcycles or dirt bikes and thinking about every possible way to improve their summer riding experience.

To deal with this shift in demand, Rekluse would hire temporary help to run machines during the winter.

It turns out that temporary help wasn't good for business. The new operators were less productive and prone to making mistakes, which lowered the company's margins at a time when it should have been most profitable.

This problem led Al Youngwerth, who founded Rekluse in 2002, and his team to explore ways to introduce flexible capacity. At that time, Rekluse had about 250 parts in its portfolio. Serving multiple motorcycle OEMs that occasionally changed clutch assemblies while trying to innovate its own technology means that some aspects of part design change yearly.

These factors made it tricky to find a solution to Rekluse’s problem. After a bit of searching, Youngwerth met with House of Design, a robot integrator in Nampa, Idaho, about 20 miles west of Boise. Together, they collaborated to form a solution: robots that load both workholding and workpieces for machining centers.

This idea resulted in the creation of VersaBuilt, which now offers these flexible solutions to other shops. VersaBuilt created the VBX-160, a robotic machine tending system that automatically loads and unloads parts for processing in machining centers. It has a rack system, a robot located inside the cell, a controller that interfaces with the robot and machining center, and a rinse-and-dry system for cleaning parts.

VersaBuilt’s latest automation system, and Rekluse’s latest purchase, the Mill Automation System, utilizes several features of the VBX-160, replacing the industrial robot with a UR10e cobot and swapping the rack system with a cart that can be moved from machine to machine. Utilizing the cobot removes the need for a skilled robot technician and allows operators to maintain the system.

Considerations for Evolving Automation

Rekluse only needed a handful of these robot-fed machines to go from shipping orders eight weeks late during the winter months to pushing through its busy season without getting behind. Now, Rekluse has 26 VersaBuilt automation systems.

Using VersaBuilt’s products, Rekluse has seen uptime improvements while requiring less labor hours per machining hour. The shop has staff on-site during the day to load the automation systems and perform preventative maintenance, and then machines run up to 18 hours straight as needed to keep up with demand. This covers the seasonal demand swings by running machines longer as needed.

Before Rekluse could Deep Hole Drilling Inserts implement this automation setup, though, there were some steps to take. Sean Brown, Rekluse’s VP of engineering and innovation, says that in order to make a robot work in a CNC machine, the company first had to integrate pneumatic vises into the machines. This led to other considerations.

The VBX-160 and Mill Automation System come with CNC files that include a table wash program for chip management as well chip wash stations outside the CNC. Photo Credit: VersaBuilt

“You’ve got to anticipate chip control. How do I keep the fixtures clean? How do I evacuate the chips? How many parts can I run before the machine needs cleaned out? These are all things — depending on the volume of work you’re doing — that you’re going to have to Indexable Inserts go through and manage,” Brown says.

In addition to all of that, Rekluse still must train people on loading the parts into machines in case the automation solution experiences downtime. In fact, Brown says the need for ongoing training while beginning the automation process was one of the biggest surprises he noticed on a general scale.

“Automation is still relatively new for some people, so, getting comfortable with it and how our process works is a big part of it,” Brown says. “To make the whole system work, you’ve got to really understand tool life, you’ve got to understand chip control in the machines and how the operator is interacting with the part. Because that changes.”

With more standardized processes in place to allow the automation solutions to work effectively, Brown says spindle crashes and machine crashes are almost non-existent now, which has led to less downtime, too.

The VBX-160 and Mill Automation System use VersaBuilt’s MultiGrip vises and soft jaws to hold parts. Photo Credit: VersaBuilt

Workflow Changes

Like any shop, Rekluse was trying to make as many parts as possible, as fast as possible. Still, it had to walk a fine line between optimizing its workflow to improve process time without upending the entire process, which aims to have more uptime with less labor to meet the shop’s increased demand in its busy months.

Brown says this made it important for the company to look at its process from a holistic standpoint and remember that the machine cutting the part is only one aspect.While cutting the part is an important part of the process, Brown adds that it’s just one element of the process. To look at total process optimization from a holistic view, he suggests considering how much to optimize the total process versus one aspect of it.

For the high-mix, low-volume work at Rekluse, Brown says flexibility is a more important factor than trying to overly optimize a one-off process. An example he gives is reducing a 30-minute process down to 20 minutes. It could be possible, but it might negatively affect the stability and repeatability of that process by leading to situations like tool breakage, which could impact the uptime goal, especially if it happens at night during unattended machining hours.

Both the VBX-160 and Mill Automation System are designed to automatically load and unload parts for processing in a CNC machine, making them ideal for a lights-out machining setup. Photo Credit: VersaBuilt

Learning the Automation Software

To run an automation solution, users need to learn how to use the software. Havey says the software solution offered by VersaBuilt is parametric, meaning it’s similar to filling out a form: users enter the part, the number of operations for the part and the G code for those operations. Brown says this setup allows anyone who can run a CNC machine to easily learn and use the software with very little additional training. The software will then keep track of how many parts have been completed and how many parts are left to complete. This is all done while maintaining the flexibility to manage Rekluse’s high-mix, low-volume workload. Once a part is introduced, the software stores that part information, there is no need to reintroduce/reprogram a part, and there is no limit to the number of parts an operator can add to the system. To introduce a new part to one of the VersaBuilt automation systems, the only requirement is cutting a set of jaws.

“That’s what I need my customers to know how to do, is make their parts,” Havey says. “And if they know how to make their parts, which they typically do, we can absolutely help them automate those parts. And one of the ways we’ve done that is by taking this parametric approach to the software.”

VersaBuilt has kept this same approach with its latest product, the Mill Automation System, which uses the same software to automate a CNC mill in high-mix environments. It has been a long road, but with new lines of automation solutions out at VersaBuilt and what Brown calls a calm, “steady Eddie” shopfloor at Rekluse, the shop has come a long way from its formerly frantic winter months.

“It’s definitely a journey, right? And I think we were lucky because we had a lot of support from (Youngwerth),” Brown says. “That’s basically like, ‘Hey, we’re going to push this through.’ And where some businesses might have an opportunity to be like, oh man, I don’t know if we can realize all of this, we had kind of made the decision and went for it.

“And I guess that’s the thing that kind of came out of this journey was, it’s going to be impactful.”

Landscape Photo Credit: VersaBuilt
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Thread milling is becoming more popular for a few reasons, says Jamie Rosenberger,? threading tool product manager for Allied Machine and Engineering, manufacturer of holemaking and finishing tools. For one, she says, most new CNC machine tools now offer helical interpolation as a standard feature. (This simultaneous XYZ motion of a spinning thread mill into a part’s hole is required to enable the tool, which has a body diameter that is only a fraction of the hole diameter, to cut the threads.) Therefore, new machinists and programmers who have “cut their teeth” on this type of newer machine tool technology seemingly are more open to considering thread milling as a viable alternative to traditional tapping operations.

In addition, Ms. Rosenberger says thread milling is particularly well-suited for challenging, expensive materials, such as tool steel, stainless steel and high-temperature alloys. In fact, Allied Machine and Engineering’s new AccuThread T3 line of thread mills was designed specifically for these applications.

She explains that during tapping operations, the tap is completely engaged with the workpiece, which results in a good bit of heat generation because the tap’s cutting edges do not get a chance to cool down and coolant has a tough time reaching them. This is particularly problematic when tapping high-temperature alloys, commonly used for aerospace and oil/gas applications, because those materials resist heat rather than absorb it. As a result, all the heat generated during tapping is directed into the tap. This, combined with the high tool pressure resulting from multiple teeth being engaged with the material, can cause the tap to wear prematurely or even break off in the hole. The latter scenario might require time-consuming rework or cause the workpiece to be scrapped, which can be costly given that threading is typically one of the final machining operations performed on a part. These considerations are what make thread milling more attractive to some shops, especially those threading expensive workpiece materials, even though thread mills are more expensive than taps.

That said, it also can be challenging to machine threads in high-temperature and hardened materials using conventional thread-milling tools that machine a complete thread in one 360-degree helical movement (for example, a thread mill that has a sufficient number of cutting edges to mill the entire thread profile into a 0.75-inch-deep hole in one helical rotation). The high cutting pressure generated because all cutting edges are simultaneously engaged with the material can cause tool deflection and poor thread finish.  

Conversely, Allied Machine and Engineering’s AccuThread T3 solid carbide thread mill with proprietary, multi-layer AM210 PVD coating cuts essentially one thread at a time in a continuous helical motion into a hole, which minimizes tool pressure and the risk of deflection. Although these tools have three teeth, the first performs the bulk of the thread-cutting action and the other two essentially clean the threads it creates. Therefore, there is little cutting pressure on the tool, so deflection typically is not problematic. In addition, during thread milling, the cutting edges have a chance to cool, because they are not constantly in the cut and it is easier for flood coolant to reach them.

What is also advantageous about the AccuThread T3 is that the tool is spun counterclockwise to enable it to perform climb milling as it is moved helically in a clockwise motion down into a hole when creating a right-handed thread. With climb milling, a tool’s cutting edge creates a “thick-to-thin” chip. That is, it forms the thickest part of the chip when it engages with the material and creates the thinner portion of the chip when it exits the cut. This generates less deflection than conventional milling (in which the tool effectively rubs on the material as it engages to create a “thin-to-thick” chip) and results in more effective chip evacuation to minimize chip re-cutting.

Thread-Milling Tips

Given the benefits that thread milling offers, Ms. Rosenberger says Allied Machine and Engineering still gets questions about DNMG Insert how best to leverage this technology. Here, she provides a few tips for shops that are considering thread milling:

• As opposed to tapping, thread milling can provide better hole quality while minimizing the risk of scrapping parts, which is especially important when parts are large and expensive. However, it is not the best threading solution for all applications. Tapping is still typically preferred when producing threads that have length-to-diameter ratios of more than 3:1.

• Think of thread milling like most other machining practices. The more stock to be removed or the more challenging the material, the more passes that may be required. For example, coarse thread pitches might require multiple passes. 

• Climb milling is always preferred to conventional milling due to reduced tool tungsten carbide inserts deflection and less generated heat.

• Always use cutter compensation when thread milling. This enables you to control the precise diameter of the thread without risking scrapping the part due to creating a thread diameter that is too large.

• Always use rigid toolholders. During cutting, thread mills experience radial side pressure and should be securely clamped in toolholders such as power milling chucks, hydraulic chucks, shrink-fit holders or end-mill holders. ER collets should not be used for thread milling.

• Don’t spend time writing your own thread-milling routines. Many software packages are available from thread-mill manufacturers, such as Allied Machine and Engineering’s InstaCode, to save you time by providing the code to you.

The Carbide Inserts Blog: https://howardgene.exblog.jp/

The N-STEP Planner helps organize information derived from a part file so that a well-developed process plan for the part can streamline the CNC programmer's input to CAM.

CAM software suppliers continue to boost programming productivity and effectiveness with developments that improve one or more of the following areas: user interaction, computer processing time and machining cycle time. For example, Surfware's TrueMill technology takes a new approach to generating tool paths for milling. This tool path engine uses an algorithm that maintains a constant angle of tool engagement rather than a constant stepover. The company says this approach not only reduces cycle time, but also extends machine and cutting tool life.

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What do CNC programmers do? Chiefly, they make sure that the part program will be executed by the machine tool successfully to make a good part. They apply their knowledge and judgment, gained by experience, to the choices that must be made for CAM software to function properly. CNC programmers are gap-fillers.

These gaps Cemented Carbide Inserts exist because design systems have not yet matured to the point that they can supply all of the digital information needed to automatically program a machine tool. In short, CNC programmers know what nobody else does. That is, they know the best way to make this part on this machine at this place at this time.

Prediction:?
Programming of CNC machine tools will continue to rely on proprietary CAM software.

Because CNC programmers are very effective at applying this knowledge, their role in machining is likely to stick around for a while. It seems that companies would do well to invest in whatever hardware and software tools help maximize the productivity of their programmers.

CAM software developers are taking many strides to make the CNC programming function more streamlined and highly Coated Inserts automated. Some of the most important of these developments include:

Knowledge-based systems—libraries, look-up tables and databases that capture the preferences and best practices of a shop's machining technology.

Specialized algorithms—applets and calculation formulas designed to meet specific programming requirements in certain applications. Various options to maximize roughing routines are some examples. Algorithms for generating specialized tool paths to produce a fine finish in high speed machining are others.

Feature recognition—the ability to identify machinable features based on sets of associated geometry elements. The most progress has been made with holes and pockets.

Verification—animated displays that preview the programmed tool moves for visual detection of potential collisions, excessive air cutting, synchronization of multiple axes and other results that determine the effectiveness of a part program.

Optimization—software features that seek to maximize feed rates based on values representing workpiece material characteristics, cutting tool performance and accuracy requirements, given the constraints imposed by workpiece geometry.

CAM developers will continue to make improvements along these and other software fronts, giving shops significant productivity gains in CNC programming output.

But how far can CAM go with automation? Can the CNC programming function be completely automated, bypassing the input of the programmer altogether? Is it wise to exclude the flexibility and unique expertise that the involvement of a CNC programmer brings?

For many machining operations, the programmer's contribution represents a key part of the shop's competitive advantage. On the other hand, CNC programming represents a bottleneck and a weak link. Losing a CNC programmer can seriously impact production flow. Likewise, human intervention works against the consistency, the exchangeability of data files and the transportability of machining operations.

Bypassing The Programmer

The most ambitious effort to completely automate CNC programming has been STEP NC, an extension to STEP, the STandard for the Exchange of Product model data. STEP NC is intended to enable product model data to serve as direct input to a CNC machine tool. It eliminates separate files of tool paths and the use of G and M codes as machine instructions. It also makes post processing unnecessary.

STEP is the international standard that specifies a neutral data format for digital information about a product. It allows this data to be shared and exchanged among different and otherwise incompatible computer platforms. STEP NC standardizes how information about CNC machining can be added to parts represented in the STEP product model. By using STEP NC to capture instructions about what steps to follow for machining the part, the "producability" of this part would not be affected by the availability a certain brand of control unit, programming system or post processor.

A full implementation of STEP NC would involve equipping machine tools with CNCs customized with special software. This software enables the CNC to interpret the STEP-NC data -directly and use the information to machine the part without a conventional G-code program. With STEP NC, all the data required to make a part are included in one AP-238 file. (Under the ISO STEP standard, STEP NC is designated as AP-238. It is an "application protocol," one of the sets of definitions for data related to a particular industry or type of product such as, in this case, machined parts.)

This approach contrasts with the conventional approach, wherein the digital information about machining a part is locked up in traditional M- and G-code (RS 274D) data. This information may reside only with an external supplier, such as the job shop contracted to machine the parts.

Likewise, the data may be valid only as long as that shop has the original or compatible resources used to generate it. Changes to these resources—if the CAM software is no longer supported, or if the machine tool or its control unit is replaced, for example—are likely to occur before the product's life cycle expires, thereby jeopardizing the availability of machined parts critical to the product.

When fully implemented, STEP NC would make "art-to-part" machining a reality. Unfortunately, implementation by industry has been spotty. Not many CAD/CAM software developers or machine tool control builders have embraced the concept enthusiastically. As a result, there are not enough commercial products to give implementing STEP NC the required "critical mass."

Whether or not STEP NC is widely adopted, it seems inevitable that product model databases will eventually lend themselves to some form of direct CNC machine input and that this option will prove cost-effective for many companies operating in a globally collaborative manufacturing environment.

Getting Part Prints In Step Digitally

Whereas STEP NC standardizes how information about CNC machining can be added to parts represented in the digital STEP product model, N-STEP is being developed so that machining and manufacturing information contained in non-digital sources can be captured in a STEP-compliant format. This initiative underscores both the urgency and the complexity of implementing data-exchangeability standards. It also indicates why marketplace resistance continues to impede the implementation of standards that would facilitate full automation of CNC programming.

N-STEP is short for National Automotive Center STandard Exchange of Product Data. NAC is part of the U.S. Army Tank-Automotive and Armaments Command (TACOM). N-STEP was launched so that the military can more quickly manufacture repair and replacement parts to keep its equipment available for battlefield deployment. Because much of this equipment was originally designed and manufactured with design and engineering data saved only as blueprints or 2D CAD files, complete digital representations of this information are not available. That means the data can't be transmitted electronically or used as input for manufacturing operations such as programming for CNC machine tools.

N-STEP is a suite of software products that enables users to capture complete and unambiguous product data, with the manufacturing features, dimensions and tolerances, material callouts, properties (hardness, surface finish and so on), and other data in a single, cohesive associative file. This file complies with the formats specified in STEP AP 224 and 203, which define machinable features and machining operations. N-STEP is a defense program that implements STEP; N-STEP is not part of the ISO standard development effort.

The suite of N-STEP software was created by the South Carolina Research Authority. The software is currently available for use under licensing agreements. It has three main modules.

The N-STEP Translator puts data from a drawing or a CAD file into an electronic format that makes sure the information from the original source is properly interpreted. In this module, a series of menus queries the user about attributes and important features of the part. Unless all of the questions are answered and ambiguities or conflicts are resolved, the Translator will not allow the user to proceed. Thus, no information is missing or unreliable when applied downstream.

The N-STEP Validator is used to manually verify the correctness of the files generated by the N-STEP Translator. It displays the product model so that the user can examine each feature and check the information against the legacy data. Any errors or omissions are compiled in a report that is sent to appropriate personnel for changes or clarifications.

The N-STEP Process Planner is an application that imposes a systematic and consistent discipline for creating a written plan detailing the processes required to manufacture an individual part or assembly. Time estimates, costs and procedural intents are entered into the database. This data can be used for quoting. The process plan created by this module is designed to streamline the CNC programmer's input to a CAM package to generate CNC part programs. To the extent that it eliminates guesswork and redundant planning steps, it offers significant savings.

Because N-STEP is defense-related, large military contractors have a strong incentive to adopt it. However, N-STEP currently runs on a UNIX computer platform. This will be a serious obstacle to adoption in the wider base of U.S. job shops, where Windows-based PC platforms predominate. TACOM is seeking wider commercialization of N-STEP-related standards, but migrating to other computer platforms and establishing a more realistic pricing structure are clearly necessary for significant market penetration.

Cost-Effective CAM

As product model databases become more complete and standardized, the CNC programming function will become more automated. In some cases, CNC programming may go away altogether. Most manufacturers, however, will choose to retain some decision-making for experienced CNC programmers. Their intervention will give the manufacturer an advantage in flexibility and optimization. Because commercially available CAM software highly automates and streamlines this input, this approach will remain viable in the foreseeable future.

The Carbide Inserts Blog: https://blog.goo.ne.jp/markben

Carbide milling cutters are milling cutters made of cemented carbide. To understand the cemented carbide milling cutter, we must first know what is a hard alloy. The cemented carbide is based on the carbide (WC, TiC) micron powder of high hardness refractory metal, with cobalt (Co) or nickel (Ni). Molybdenum (Mo) is a binder and is a powder metallurgy product sintered in a vacuum furnace or a hydrogen reduction furnace.

Contents hide 1Carbide milling cutter classification 2Carbide milling cutter's application 3Carbide milling cutter milling method 4Carbide milling cutter's maintenance 5Carbide milling cutter‘s selectionCarbide milling cutter classification

Carbide milling cutters are mainly divided into: solid carbide milling cutters | carbide straight shank milling cutters | carbide saw blades milling cutters | carbide auger milling cutters | hard alloy machine reamer milling cutters | Carbide end mills | Carbide ball end mills

Carbide milling cutter's application

Carbide milling cutters are generally used in CNC machining centers and cnc engraving machines. It can also be loaded onto a conventional milling machine to process some hard and uncomplicated heat treatment materials.

1. Carbide cylindrical milling cutter: used for horizontal milling machine processing plane. The teeth are distributed on the circumference of the milling cutter and are divided into straight teeth and spiral teeth according to the tooth shape. According to the number of teeth, there are two kinds of coarse teeth and fine teeth. The spiral tooth coarse-tooth milling cutter has a small number of teeth, high tooth strength and large chip space, which is suitable for rough machining; the fine-tooth milling cutter is suitable for finishing.

2. Carbide face milling cutter: It is used for vertical milling machine, end milling machine or gantry milling machine. It has cutter teeth on the end face and circumference, and also has coarse teeth and fine teeth. The structure has three types: integral type, insert type and indexable type.

3. Carbide end mill: used to machine grooves and step surfaces, etc., the teeth are on the circumference and end faces, and can not be fed in the axial direction during operation. When the end mill has a tooth that passes through the center, it can be fed axially.

4. Carbide three-face milling cutter: used to machine a variety of grooves and step surfaces, with teeth on both sides and circumference.

5. Carbide angle milling cutter: used to mill a groove at a certain angle, there are two kinds of single angle and double angle milling cutter.

6. Carbide saw blade milling cutter: used to machine deep grooves and cut workpieces, with more teeth on the circumference. In order to reduce the friction during milling, there are 15'~1° secondary declinations on both sides of the cutter. In addition, there are keyway milling cutters, dovetail milling cutters, T-slot milling cutters and various forming cutters.

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Carbide milling cutter milling method

The milling direction of the carbide milling cutter relative to the workpiece and the direction of rotation of the milling cutter are mainly the following two milling methods:

The first is down-cutting. The direction of rotation of the milling cutter is the same as the direction of feed of the cutting. At the beginning of the cutting, the milling cutter bites the workpiece and cuts the last chip.

The second type is up-cut milling. The direction of rotation of the milling cutter is opposite to the direction of feed of the cutting. The milling cutter must slide over the workpiece before starting the cutting. The cutting thickness starts at zero and the cutting thickness reaches the end of the cutting. maximum.

When milling, the cutting force presses the workpiece against the table, and the cutting force causes the workpiece to leave the table during up-cut milling. Since the cutting effect of the down-milling is the best, the down-cutting is usually preferred. Only when the machine has a thread gap problem or if there is a problem that can not be solved by the down-milling, the up-cutting is considered.

Each time a cemented carbide milling insert enters the cutting, the cutting edge is subjected to an impact load, which depends on the cross-section of the chip, the material of the workpiece and the type of cutting. Ideally, the diameter of the milling cutter should be larger than the width of the workpiece. The centerline of the milling cutter should always be slightly separated from the centerline of the workpiece. When the tool is placed against the center of the cutting, burrs are easily generated. The direction of the radial cutting force will change continuously as the cutting edge enters and exits the cutting. The machine tool spindle may vibrate and be damaged. The blade may be broken and the machined surface will be rough. The carbide milling cutter will be slightly off center and the cutting force direction will be No longer fluctuating, the cutter will get a preload.

Carbide milling cutter's maintenance

When the cemented carbide milling cutter axis line and the workpiece edge line coincide or approach the edge line of the workpiece, the situation will be very serious, the operator should do the relevant equipment maintenance work:

1. Check the power and stiffness of the machine to ensure that the required cutter diameter can be used on the machine.

2. The overhang of the tool on the spindle is as short as possible, reducing the influence of the axis of the milling cutter and the position of the workpiece on the impact load.

3. Use the correct milling pitch suitable for this process to ensure that there are not too many blades to engage the workpiece at the same time to cause vibration during cutting. On the other hand, ensure that there are enough blades when milling narrow workpieces or milling cavities. Engages with the workpiece.

4. Make sure that the feed per blade is used to achieve the correct cutting results when the chips are thick enough to reduce tool wear. The indexable insert with positive rake groove shape provides smooth cutting results and lowest power.

5. Use a milling cutter diameter that is appropriate for the width of the workpiece.

6. Use the correct lead angle.

7. Place the milling cutter correctly.

8. Use cutting fluid only when necessary.

9. Follow tool maintenance and repair rules and monitor tool wear.

Proper maintenance of carbide milling cutters can extend Cemented Carbide Inserts tool life and increase work efficiency.

Carbide milling cutter‘s selection

Milling stainless steel except end mills and some end mills and carbide as milling cutter materials, all other types of milling cutters are made of high-speed steel, especially tungsten-molybdenum and high vanadium high-speed steel have good effect, the tool Durability can be 1 to 2 times higher than W18Cr4V. Carbide grades suitable for making stainless steel milling cutters are YG8, YW2, 813, 798, YS2T, YS30, YS25 and the like.

The effect of spray cooling is the most significant, which can increase the durability of the milling cutter by more than one time; if it is cooled by a general 10% emulsion, the cutting fluid flow should be sufficiently cooled. When milling carbide with carbide milling cutter, take Vc=70～150m/min, Vf=37.5～150mm/min, and adjust it according to the alloy grade and Carbide Inserts workpiece material.

The adhesion and fusion of stainless steel are strong, and the chips are easy to adhere to the cutting edge of the milling cutter, which deteriorates the cutting conditions. When the milling is performed, the cutting edge first slides on the hardened surface, which increases the tendency of work hardening; impact during milling The vibration is large, which makes the milling cutter blade easy to chip and wear.

When milling stainless steel, the cutting edge must be sharp and bear the impact, and the chip pocket should be large. Large helical angle milling cutters (cylindrical milling cutters, end mills) can be used. The screw angle b is increased from 20° to 45° (gn=5°), and the tool durability can be increased by more than 2 times because the milling cutter works at this time. The rake angle g0e increases from 11° to over 27°, and the milling is light. However, the b value should not be large, especially the end mill should be b ≤ 35 °, so as not to weaken the teeth.

The stainless steel pipe or thin-walled parts are processed by the wave edge end mill, the cutting is light, the vibration is small, the chips are brittle, and the workpiece is not deformed. High-speed milling with carbide end mills and milling of stainless steel with indexable end mills have achieved good results.

Milling 1Cr18Ni9Ti with silver end mills with geometric parameters gf=5°, gp=15°, af=15°, ap=5°, kr=55°, k′r=35°, g01=-30° , bg=0.4mm, re=6mm, when Vc=50～90m/min, Vf=630～750mm/min, a′p=2～6mm and the feed amount per tooth reaches 0.4～0.8mm, the milling force is reduced. Smaller 10% to 15%, milling power is reduced by 44%, and efficiency is greatly improved. The principle is that the negative chamfer is ground on the main cutting edge, and the built-up edge is artificially generated during milling, so that it can be cut instead of the cutting edge. The front angle gb of the built-up edge can reach 20~~302, due to the lead angle The effect is that the built-up edge is caused by the thrust generated on the rake face parallel to the cutting edge to become the auxiliary chip, thereby taking away the cutting heat and lowering the cutting temperature.

When milling stainless steel, it should be processed by the same method as possible. The asymmetrical cross-milling method can ensure that the cutting edge is smoothly cut off from the metal, and the contact area of the chip bonding is small, and it is easy to be smashed under the action of high-speed centrifugal force, so that the chip impacts the rake face when the tooth re-cuts into the workpiece. Peeling and chipping improve the durability of the tool.

Stainless steel materials are widely used and can be encountered in machining, milling, drilling and tapping. But because stainless steel has different characteristics than other general materials, processing stainless steel has become a big problem for technicians!

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