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What is a Class A Die?
What is a Class A Die? By: Jim Szumera - MACOR Published on: 08/16/2016
What is a Class A DIE?
I have an idea what a class a die should be. It has never been formally defined. It is a personal perception based on one’s own background and experience in the Tool and Die Industry. It may mean one thing to a manufacturing engineer and something totally different to a tool and Diemaker. One of our clients engaged us to help them bring a new product to market. The product utilized 28 different stampings. Part of our responsibility was to source the tooling and production in the United States. I put together a spreadsheet and sent out the bid packages. The production costs were relatively competitive. I was totally amazed at the variations in the tooling costs. They were all over the map. I had received prices ranging from $45,000 to $325,000 for the same tool. This issue was prevalent across all 28 tools. Everyone quoted a class A tool. I don’t think anyone quoted a class B die. What actually happened? All the suppliers chosen were the experts in the field. It became a question of perception and personal preference of what constitutes a class A die. The pricing was not acceptable, so I decided to create a tooling specification to define a class A die, or better yet, define our needs. The bid packages were sent out again along with the tooling specification. To no one’s amazement, the return bids were all competitive within 10%. This allowed me to now focus on the logistics, of delivery, terms and other valuables.
In creating a tooling standard or specification, it is important to focus on several factors. The quantity requirement or product life cycle is first on my list. The next critical criteria are rates of production, product tolerance, tooling support, maintenance, safety and design. It is a good practice to keep the tooling standard user friendly and only address those attributes which are required to meets product specification.
Let’s look at an example. Assuming we have a product that must ship large quantities per month and the life cycle is 5 years. Knowing also the tolerances, I can now define the tooling parameters. The die design itself can stipulate all the attributes, or it can be expressed in a separate document.
The design attributes can include assembly views, material lists, detailed drawings, general set up instructions, and possibly a maintenance work instruction. The design can be either separable (one detail per drawing with its own identifier for control and reorder) or inseparable (many details per sheet utilizing one tool number). You can specify that all drawing requirements comply with the latest DOD STD or ANSI Y14.5 etc.
Let’s now look at some tooling attributes. The die shoe or die set can be specified 2 or 4 post with ball cages or pins. You can also specify thickness, shut height, and mounting bolt pattern. Depending upon part tolerance the die shoe flatness can be specified (.0005 per linear foot). Avoid using such terms as “commercial” or “precision” unless accompanied by a tolerance. The type of steel can also be specified. A hot rolled crs, Aluminum or 4140 as an example.
The type of materials for the tooling components should also be specified. The method of fastening the components to the shoe can also be specified. Each component should be permanently identified with tool number and rev level and material. You may also want to specify utilizing the WEDM process for die buttons, punches, strippers and inserts. Any components with large cut outs should be stress relieved after WEDM, in order to avoid pre mature failure or cracking.
The following is a list of other attributes to consider in developing a die standard:
1. Pneumatic, electrical and hydraulic connections are to be quick disconnect type
2. Anti-deflection devices may be specified where applicable. These devices can be guided strippers or heel blocks. You can also specify the method of attachment.
3. Coatings and surface treatments can be specified.
4. Hardware can be specified such as springs, fasteners and pins. This is especially important during this age of counterfeit and imported fasteners. You may want to specify domestic proven brands. The tooling damage done due to a fastener failure can be enormous. You may want to specify all the same size fasteners for mounting. This can reduce maintenance time. All hardware should be standard and readily available.
5. A method of starting or locating the strip in the die to initialize a tooling run.
6. Tooling identification may be required by a stamped and lettered tag attached to the shoe.
7. Slug retention devices can be specified to be incorporated into the die side of the tool. This can greatly reduce maintenance time as well as reduce downtime during production.
8. In certain types of dies I may want to specify safety devices such as miss feed detection, end of coil, part out and double thickness indicators.
9. You can specify the punch and die clearance desired, as well as the slug clearance, along with the amount of punch penetration into the die.
10. Back up plates may be required to support the punches and die components from sinking into the shoe.
11. You may want to specify any safety features required by OSHA
This is an example of some of the attributes a tooling specification can contain. Yours may need to be better defined or contain certain attributes to coincide with your production efforts and objectives. A tooling standard goes a long way in controlling costs and eliminating short cuts.
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Gage R&R 101
Gage R&R 101 By: Jim Szumera - MACOR Published on: 07/28/2016
Quality is job one. But often times I find myself in a constant battle with quality engineers, the customer and the production floor about the same issue. Many times I have had good product rejected and bad product shipped. The devil lies in the details.
Throughout my career I have been battling the issue of quality, whether it be manpower, method, material, or machine. The methods between the tooling guys, the production floor, quality and the customer should all be consistent and if possible, the same. The machines or gauges must fit the criteria or part specifications to be checked. For example, if I am checking an outside diameter with a specification of +/- .002, I would not choose calipers as my method. The variation in the calipers is too great that I can use up a good portion of my part tolerance, good or bad. The following Wikipedia explanation on ANOVA Gauge R&R may be helpful in dealing with shop floor dilemmas.

Gauge R&R (gauge repeatability and reproducibility) is a measurement systems analysis technique that uses analysis of variance (ANOVA) random effects model to assess a measurement system.
The evaluation of a measurement system is not limited to gauges but to all types of measuring instruments, test methods, and other measurement systems.
The Purpose of Gauge R&R is to measure the amount of variability induced in measurements by the measurement system itself, and compares it to the total variability observed to determine the viability of the measurement system. There are several factors affecting a measurement system, including:
· Measuring instruments, the gauge or instrument itself and all mounting blocks, supports, fixtures, load cells, etc. The machine's ease of use, sloppiness among mating parts, and, "zero" blocks are examples of sources of variation in the measurement system. In systems making electrical measurements, sources of variation include electrical noise and analog-to-digital converter resolution.
· Operators (people), the ability and/or discipline of a person to follow the written or verbal instructions.
· Test methods, how the devices are set up, the test fixtures, how the data is recorded, etc.
· Specification, the measurement is reported against a specification or a reference value. The range or the engineering tolerance does not affect the measurement, but is an important factor in evaluating the viability of the measurement system.
· Parts or specimens (what is being measured), some items are easier to be measured than others. A measurement system may be good for measuring steel block length but not for measuring rubber pieces, for example.
There are two important aspects of a Gauge R&R:
· Repeatability: The variation in measurements taken by a single person or instrument on the same or replicate item and under the same conditions.
· Reproducibility: the variation induced when different operators, instruments, or laboratories measure the same or replicate specimen.
It is important to understand the difference between accuracy and precision to understand the purpose of Gauge R&R. Gauge R&R addresses only the precision of a measurement system. It is common to examine the P/T ratio which is the ratio of the precision of a measurement system to the (total) tolerance of the manufacturing process of which it is a part. If the P/T ratio is low, the impact on product quality of variation due to the measurement system is small. If the P/T ratio is larger, it means the measurement system is "eating up" a large fraction of the tolerance, in that the parts that do not have sufficient tolerance may be measured as acceptable by the measurement system. Generally, a P/T ratio less than 0.1 indicates that the measurement system can reliably determine whether any given part meets the tolerance specification. A P/T ratio greater than 0.3 suggests that unacceptable parts will be measured as acceptable (or vice-versa) by the measurement system, making the system inappropriate for the process for which it is being used.
Gauge R&R is an important tool within the Six Sigma methodology, and it is also a requirement for a Production Part Approval Process (PPAP) documentation package.
There is not a universal criterion of minimum sample requirements for the GRR matrix, it being a matter for the Quality Engineer to assess risks depending on how critical the measurement is and how costly they are. The "10x2x2" (ten parts, two operators, two repetitions) is an acceptable sampling for some studies, although it has very few degrees of freedom for the operator component. Several methods of determining the sample size and degree of replication are used.

All gauging techniques and systems should be defined at the design review stage between customer, quality, production and tooling.
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World Class Die Maintenance
World Class Die Maintenance By: Jim Szumera - MACOR Published on: 06/9/2016
Building World Class Die Maintenance
Die maintenance is a service organization, much the same as an automobile dealership service department. Most dealerships cannot make the absorption rate to break even, so it is a necessary evil. Dealership service departments thrive on factory recalls. This is because they can bill back the hours to the manufacturers. It really cannot operate as a profit center, but in today’s economy it still must be world class. This is due mainly to the fact that they have to service what they sell and they are dealing directly with their customers on a personal level. Service is an integral part of any business, but because it cannot make a profit on its own, it usually is neglected and thus underperforms.
How does your shop measure up? First we would have to separate out the specialty or niche tooling that you may deal with. That is not to say it doesn’t the fit the mold. Specialty or niche tooling may require a unique approach to certain portions of die maintenance. For instance, a special grinding fixture may be needed to service and sharpen unique punches or forms. A special handling device or equipment may be required. Aside from the specialties, the desired results are almost always the same; reduced turnaround time to production; a better tool life cycle between maintenance, increased press uptime, improved first time set ups, and reduced overall costs. The ingredients we look at are equipment, procedures, drawings, spare parts, quality, ergonomics, and staffing.

A world class die maintenance operation has all the tools required at hand. This would include, but not limited to machine tools than can meet or exceed finish and tolerance requirements. Machine availability should never come into question. The equipment and machines should address every possible common operation needed to service the dies properly and expeditiously. Surface grinder, drill press, vertical mill, lathe, bead blaster, degreasing sink, hydraulic press make up the major portion of machine tool needs. Support equipment such as grinding fixtures, diamond dressers, radius dressers, Norbide dressers, grinding wheels, surface plates, V blocks, magnetic chucks, demagnetizer, etcher, hand held die grinders, bench grinders, belt sander, polishing lathe, lapping plate, laps, stones, pneumatic or cordless torque wrenches, shim fabricators is needed and should be placed conveniently and with purpose in the area. All pertinent die hardware, including springs, nitrogen cylinders, screws, shoulder screws, shoulder screw shims for lengthening and shortening, dowels, shim stock, markers, connectors, fittings, should be visible and readily available. Depending upon the size of the tooling and work area, these items should be organized and made visible and mobile. Looking for shims and making shims can increase actual maintenance time by as much as 50%. Shims should be ready made, organized and readily accessible.

Procedures or die maintenance work instructions should be formally integrated documents or simple task checklists can be a good substitute. In any case these should be accessible and visible in the work area. Tooling drawings and part print drawings, along with any associated quality documents must be readily accessible. This may require die books or a PC with read only and print capability. Effective wall charts work well. Most die service, diagnosis and repair is usually left up to the tool and die maker. The die is then released to production as he or she sees fit. There are no checks and balances at this point. The die should be checked and verified by a “die checker” as a final step. Remember, if you have 10 toolmakers you will get 10 different renditions of what a preventative maintenance should consist of. That is not to say that anyone is wrong, just different. That makes process improvement next to impossible.

Specific die components such as punches bushings, pilots, die sections and blocks, sensors and spring pins can be pre kitted and ready for change over, as opposed to disassembly, sharpen and reassemble. The expended details can be sharpened by a grinder hand at a later time. This will eliminate actual sharpening and handling by the die technician during maintenance and reduces the turnaround time tremendously. Utilizing spare parts in this manner speeds up the entire process. Many shops keep a tooling inventory for emergencies and tool breakage. This dollar investment should be utilized to cut costs, not increase costs.

Tool quality and inspection should also be at point of use. Drop indicators, surface gages, gage pins, surface texture gage, shim gages, angle gages, gage blocks, micrometers, calipers, spring tester, hardness tester, and comparator make up a partial list of the measurement and inspection tools needed and should also be readily available. Depending upon certain shop variables, a tooling inspection area could be set up separate but should always be convenient and accessible. The die maintenance inspection area should be capable of inspecting production parts as well as the tools, dies and punches. Granted, some items may require a CMM and it may not be practical in the die repair area. Measure, measure, measure, inspect! Anything that goes into a production tool needs to be verified, if only the criticals.

Ergonomics and Kaizen play an important role in reducing costs by simplifying the process, eliminating redundancy and making for a workplace that is enjoyable to be in. Pretty heavy stuff! The days of the cabinets, loose leaf binders and index cards is over. A visible, ergonomic and safe workplace that is well lit is the solid foundation that leads to sustainability.

The right staffing of the die maintenance area can be a difficult task. Finding qualified people who can hit the ground running is not easy, if not impossible. Utilizing existing personnel as die technicians is the new future of tooling maintenance. Not only does this approach boost moral, but makes good business sense and cuts cost at the same time. The candidates should be somewhat familiar with your current press operations, know how to use calipers and micrometers, and read tooling and part print drawings. This is all that is needed. You probably have the right people working in the plant right now and just need to leverage this talent differently. Tool and Die makers are not needed in this function, if you have everything in place. You are more than half way there!

The type of production stampings one makes is not an excuse for being world class. World class is really a simple idea with good execution. A world class die maintenance function should not make shims, sharpen dies, look for tools, or go somewhere else for something. It is not a place with poor lighting where you put a couple of machines, a ball peen hammer and some sand paper and expect results. It is an area staffed with the right people, the right tools, the right space, and the authority to make decisions and run itself.
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