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Vancouver Tel: 604-899-8977 Fax: 604-899-0959

marcus@implant-mechanix.com

TIPS FOR CLIENTS LOOKING TO SAVE COSTS WITH WIRE EDM

Most of our clients are purchasers, engineers and machinists, trying to reduce costs and optimize design. We have assembled this sheet of helpful points to help you minimize costs and improve design for manufacturability. Refer to our tips below for purchasers and designers and engineers.

TIPS FOR PURCHASERS

  1. Order as many parts as you can every time you place an order.
    Each order requires me to set up the machine; you want to amortize the setup fee into as many parts as possible.
    Also, bigger orders often allow me to cut more parts from a bigger block so you get a better deal from the automation that becomes possible.
    Third, with a bigger order, I can justify tuning the program and cutting conditions to speed up the cut to the maximum possible.
    Fourth, I can justify making a better, more efficient setup
    Fifth, if your parts are thin, I can stack them and greatly reduce the price per part.
  2. Supply your own material and avoid paying my markup
  3. Be flexible on your delivery date so you can capitalize on the best rates.
    If you have a hot rush job, I will do my best to accommodate your needs, but you will pay more to be pushed to the head of the line. Rush fees typically add 50% to the cost of a job.

TIPS FOR DESIGNERS AND ENGINEERS

  1. Set your tolerances and finish requirements as liberally as possible
    Make them tight only where you need to.
    The new machine can easily cut within 0.001” on a single pass but there will be significant geometric errors mostly from wire lag and material movement as the stresses in it relax when it’s cut. Expect most single pass cut parts to be within 0.003” but they will often be much better than that…it all depends on how the stresses move the developing part around.
    Here’s an example of stress release in a cut: you can see how much the cut kerf has collapsed.

    Multiple finish passes are more expensive but will get you micron level precision if you need it.
    If you specify on your print, which features need to be cut accurately, I can skim cut only those features and leave everything else with first pass precision and finish.
    The same is true for fine finishes…specify them only where you need them.
    The easiest way to communicate this is to mark the print or model with colors where you need special precision or fine finish.
  2. Set your minimum internal radii bigger than 0.0053” (0.135mm)
    The machine is normally set up with 0.010” (0.25mm) wire…I can change it to 0.006” (0.152mm) wire to give you 0.0033”(0.084mm) but I’ll need to set up the machine specially, which incurs a wire change charge of $80.00.
    Small wire also cuts much more slowly and cannot cut very tall workpieces; 2” (50mm) is pretty much the upper limit for reasonable machining times with 0.006” wire.
    If you need a particularly sharp internal corner, ask me for design options for clearing the corner.
  3. Accept cutoff stubs:
    All male parts need to be cut while attached to their raw stock by a small tab (at least one tab, sometimes more).
    Once the part is finished the tab is cut through with the wire and leaves a small stub sticking out from the surface of the part.
    It is possible to remove this vestige perfectly, but it requires making a fixture to hold the part, and successively skimming the vestige away until it just disappears.
    This is expensive to do, compared to finding a place where the stub doesn’t matter and just leaving it.
    Alternatively, if the stub location is well chosen, it can be removed by surface grinding, milling or even hand stoning under the microscope.
    I will help you find the best locations on your part and decide on a strategy with you that gives you what you need at the best possible price.
    Here is a part still attached to its stock and about to be cut free leaving a stub:

    The tab will be left on the corner where it doesn’t matter.
  4. Make your own:
    If you have access to an in-house machine shop you can save considerable cost by building your own fixtures, preparing your own stock, finishing your cutoff vestiges etc.
    Please do not build anything without consulting with me first…there are some specific things you must do to make a useful job of it.
    None of it is complicated, but if it’s not done properly it’s worse than useless.
    You can find machinists' instructions here.
  5. Don’t forget: wire EDM can only cut electrically conductive materials
  6. Send me models (Parasolid version 11.1) or DXF files instead of PDF files for quoting.
    I need to interrogate the file to find out how long the cut path is…I can’t do that efficiently from a PDF file.
    Send them to: marcus@implant-mechanix.com
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