Setup and Fixturing
Proper workholding can reduce the chance for error and ensure that parts are machined to the proper specifications.Several considerations were shared when planning a workholding method:
1. The most common and least expensive method of workholding is vise fixturing. This method does require the part to have two parallel sides that can be gripped by vise jaws.
2. More complex parts designed without parallel edges are machined using softjaw fixturing. This is when vise jaws are cut away in the same shape as the part to be machined. Softjaw fixturing does require an extra machining step, but is still fairly cost effective.
3. Double sided tape works well for parts that don’t require flood cooling during machining but it does require large surface area for the tape to hold and the adhesive is sometimes difficult to remove after machining.
4. For larger, plate-like parts that cannot be held by a vise, through holes are used to bolt the part down. Sometimes existing holes can be used, but it can save the machinist time if the specification documents include a note stating that holes may be cut for this purpose if necessary.
5. Try to avoid multiple setups. The most cost effective parts are those without features on the side or back. This is because the machine doesn’t have to be reset and the part re-fixed.