Choosing the Best Workholding Device

Rarely is there only one way to get a job done. When it comes to securely and accurately situating material on a machine table, this is quite true. Each will vary in importance from shop to shop. Some situations will be easier than others to assess. However, understanding these four components about the job will help you find the best workholding device for your project.  

Part Size and Shape

Two of the most important factors of a good workholding setup are stability and access. Both have a direct connection to right-size workholding and finding a balance between the two is needed. If a part is too small for your fixture, consider palletizing multiple parts. However, if a part is too big for your fixture, consider upgrades if what you have is modular, or add custom pieces, if possible.

Choosing workholding that accommodates the shape of your part really comes down to whether it’s round or prismatic (has flat sides). If the parts are prismatic, most often a vise will do just fine. If the part is round, you’ll need to hold on to an outer or inner diameter on the part. This may require a collet chuck, lathe chuck or V-blocks, if it needs to go into the mill and so on.

Part Condition and Accuracy

Knowing if what’s coming through will be raw material, a casting, or partially finished parts, will also indicate what the workholding will have to accommodate. If a part has already been machined, then the size is not a variable, it’s a known controlled value. For example, a round raw bar from the mill may have an OD tolerance of ±.005", but if a part is cast, then the size may be ±.02"—could be better, could be worse. Additionally, the production environment and tooling must be suitable for the application. The accuracy of the locating and clamping surfaces on the workpiece should also be considered. Further, a clean workpiece produces the best product. When debris builds up in the clamping area of a workpiece, it may affect how the piece is being held, thus negatively affect the outcome of the entire procedure.

Production and Mix Levels

The frequency and complexity of part changeover should impact how fast you need your workholding to be. The higher the part mix and/or production level, the more changeovers. Seriously consider how much time a certain piece of workholding will require during locating and clamping. 

Selecting the best workholding system for an application ultimately leads to a better product. By sticking to wise principles in choosing the workholding solution, plus maintaining a good and open relationship with the vendor, a shop can meet all the challenges of today’s demanding production environments.

If you have additional questions, or specific use case scenarios you’d like to inquire about, contact us at (847) 882-8800 or ymzmarketing@yamazen.com