Video: Custom Workholding for Tool Regrinding
This shop uses a simple toolholding device on a machine meant for unattended tool production to regrind tools that already have their precision geometry.
Tri-State Tool Grinding in Cincinnati, Ohio, has a CNC tool grinder with a workpiece carrier intended for production grinding of carbide blanks. The small shop wanted to adapt this carrier for unattended regrinding of tools that already have the precision geometry.
The shop’s solution illustrates a point worth noticing now and again—namely, the extent to which a machine shop is routinely an inventor. Frequently, that invention takes the form of fixtures and other in-house workholding for machining centers, but this video shows it applied to the creation of a workholding device used for holding tools during regrinding.
Roughing and finishing on a single machine, using a single setup, has appeal for most shops. The advantages in time savings and accuracy are obvious. Eliminating the transport of workpieces between machines, as well as the setup for those secondary operations, is a boon for throughput. Critical features that need to maintain dimensional relationships can be much more reliably produced if machined complete in one clamping.
Optimizing a camshaft lobe grinding cycle has traditionally been based less on science and more on educated guesswork and numerous test grinds. Now, computer thermal modeling software can predict areas where lobe burning is likely to occur, in order to determine the fastest possible work speed that won't thermally damage lobes and greatly reduce the number of requisite test grinds.
Wire EDM units that swivel a horizontally guided electrode wire in a CNC-controlled E axis give this shop the workpiece clearance and flexibility to produce complex, high-precision PCD-tipped cutting tools.