Production Wire EDM Techniques That Are Efficient & Cost EffectivePublished on: April 29, 2022
Senior Project Manager
Xact Wire EDM Corp.
Wire EDM, once deemed non-traditional, has been extensively utilized across industries for many years. This unique process crafts high-precision parts from various conductive materials, serving numerous applications. In today’s world, tolerances keep getting tighter and tighter. For this reason, EDM is being used more often as it is one of the best methods for machining accurate parts. The wire electrical discharge machining (WEDM) process is, however, still considered slow by many.
However, when making two or more parts, the use of production wire edm techniques are necessary to achieve an efficient and cost-effective result. Small parts are especially good candidates for the process.
The cutting speeds have not change as much over the last 20 years or so as they did early on, so WEDM is not always consider the fastest method for producing parts.
However, by combining this unique method of machining with some old techniques, a new approach to wire cutting customer orders with several parts can be fast and practical. It is necessary to understand the scope of a production job before it commences. Many companies use ISO guidelines to ensure that procedures are in place to guide a complete understanding of the project’s requirements.
There is usually a starting point when a customer places an order for some parts and the quoted details are confirmed. The final result, the finished part, is normally what most customers stress. But the start, is just as critical as the project end, resulting in precision finished parts. Ensure the destination’s economic feasibility and confirm you’re collectively moving in the right direction. When you have production Wire Edm techniques that are efficient cost effective all you need good communication and planning are necessary to achieve a quality outcome as is the proper blank-prep layout.
The term ‘internal skim‘ rough-cuts, secures parts during skimming production, and positions the nearly finished part to align with existing details. Pre-machining features like tapped holes and blind pockets can precede the WEDM step. The part is not cut-off but instead held within the blank material. Chaining parts together in a row allows wiring more than one part simultaneously. Skimming greatly improves the accuracy and surface finish of the final part.
Additionally, stacking the parts in the blank material combined with chaining them together is in many cases the most efficient way of cutting. When cutting away the scrap and skimming the parts, WEDM often achieves maximum efficiency, especially with 2-inch thickness, considering factors like the wire diameter.
Frequently these techniques are not possible because production jobs are made from individual blanks. For example, if we have an order to make 100 parts, we start with 100 blanks (usually supplied by the customer). We then cut away anything that does not look like the part and the result is the finished product.
Every part requires time and this time multiplied by 100 starts to add up and makes the parts expensive in some cases. If possible, it is better to start with one piece of material. Applying the above-stated approach and techniques correctly enables the use of one block of raw material to produce hundreds of parts.
This internal skim approach can also be apply in multiple views. However, the use of high tolerance holding systems are now necessary. Better known as a fixture or vice, they need to be dependable. It allows us to wire a part in the machine and then to remove it from the machine to inspect it. We can inspect it on a camera (or any piece of equipment known as a video inspection station) and then reload the part to within 0.000080” of the original location.
Subsequently, we can perform additional skim cuts if needed to maintain precise tolerances. This tooling also enables us to make 90-degree rotations from the first wire operation and allows us to cut the parts again in a different plane (First in the X plane and second in the Y plane).
Doing this two, or even three times (Z plane), can yield a finished three-dimensional part using the 2D wire cuts. The chaining method, or stacking of the parts, while cutting multiple views is when production EDM is the most economical.
Instead of using only manufactured vices or holding systems, you can machine your own fixtures. We prefer to use a wire cut holding fixture and wire individual “cartridges” to hold prepped parts that are ready for wire EDM. In some cases, we are just adding another detail to an already machined or metal injection molded component. The cartridge enables us to load prepped parts on the bench while simultaneously wiring another cartridge in the machine. The wire machines use auto-positioning to repeat start points.
Hence, the operator can effortlessly move the wire machine for part inspection and resume machining with a single button press.
The visual inspection equipment can place the cartridge and record inspection data for multiple parts, saving it as required.
It is obvious that your QA department must be capable of documenting and recording the finished dimensions before doing any production EDM. WEDM is capable of fine detail and extremely tight tolerances. Your inspection equipment must be even more capable. When running production parts, it’s crucial to calibrate and maintain both the wire machines and inspection equipment properly. You certainly do not want to mass produce non-conforming parts. Monitor specific process controls throughout the entire production run for optimal performance. QA procedures such as SPC are a huge help.
Most of the wire machines today are stock with an ‘auto-threader. This is especially useful during production runs to save time and keep the wire machine running when unattended. Auto-threading creates start holes close to the finished diameter, eliminating discarding drops/slugs and saving significant time.
Also known as slugless burning, this technique is best for machining many small round holes or oval slotted cavities. The wire machine can operate in auto-thread mode, ensuring minimal downtime during machining.
Maximize wire cutting efficiency by setting up multiple blocks within the wire machine’s travel limit for slugless burning. Create a command file with stored start locations to seamlessly wire all blocks without downtime between each.
Machining very thin materials with Wire EDM proves highly cost-effective. For instance, you can stack up to two inches in height using 400 sheets of .005 thick SS shim.
Utilize a single wire path to cut the desired profile and generate 400 parts from a single material stack. Chaining small shapes together enables continuous, unattended operation, yielding 400 parts per stack efficiently.
Amid tight tolerance dimensions, selectively removing outer drop material allows skimming critical dimensions to size without cutting the entire profile.
Explore wire EDM for machining expensive or precious metals; it generates minimal chips compared to conventional drilling or milling machines. There will be less waste, and the parts can be produce very close together. The scrap pieces are much more recyclable also.
Maintain a minimum distance of .025 inches between parts during wire cutting to prevent wire arcing. Critical: Use consistent dielectric flushing (DI water) to remove Edm particulates, preventing secondary edm and ensuring smooth adjacent surfaces.
Production typically implies an assembly line of people or robots mass-producing parts or assemblies.
No doubt, Production Wire edm techniques that are efficient cost effective but In production wire edm, parts align sequentially, whether within a blank material, cartridge, or fixture, to optimize the wire Edm process.
Using the techniques mentioned above, especially if combined, will help reduce machining time and save money. Production wire Edm is one of the most accurate and precise ways to make a part. It saves time and produces parts cost effectively if used properly.
Opt for production wire edm for multi-part manufacturing, maximizing technology’s full potential.