When it comes to work-holding for carbide tool production, you are often faced with the question of whether to include additional support for the tool or simply rely on the collet clamping mechanism to provide that support and grind the tool “free-ended”.
It’s true that a tool support system like a pop-up steady or a tailstock can, in some cases increase the set-up time for a job, but you need to trade that off against the potential improvements you can gain in cycle-time.
Often thought of as an aid to tighter tolerances, the humble steady rest can also be used as a production rate amplifier. By supporting the tool, you can ramp up the feedrate without suffering tool deflection. And in the last few tools prior to an automated wheel dress, a steady rest can help maintain your tolerances and avoid breakages, even as the wheel starts to dull off.
Since no one support system suits all applications, manufacturers of modern tool and cutter grinders usually provide a choice of tool support systems from manually adjusted steady rests, right through to fully automatic, self centering, multi-diameter, multi-point clamping supports and tailstocks on programmable axes that move in perfect synchronisation with the grinding wheel to always provide support where it is needed most.
In the case of an automatic tailstock, it is even possible with an advanced system, to program the force that the tailstock will exert on the center, allowing you back it off for some operations like cylindrical grinding.
As we’ve mentioned, the main reason to support your tool is to reduce deflection of the tool during grinding. Reduced deflection will improve your tolerances, run-out and surface finish. These characteristics feed directly into a higher quality, longer lasting tool that you should be able to charge a higher price for.
But also, don’t forget to crank up your feedrate once you start supporting your tools, particularly during fluting, normally the slowest cycle in the production process. The increased support will in many cases allow you to chew through more carbide per minute without sacrificing tool quality or wheel life, further increasing your efficiency and adding incremental gains to your profitability.
Even though you might expect to wear out your grinding wheels faster using a tool support system due to your faster feedrates, supporting your tool can in some cases actually extend the life of your wheels.
The vibration that can be induced by grinding an unsupported tool can lead to chipping and wear along the edge of the wheel which can dramatically shorten the useful life of your wheel. You can minimise this undesirable effect by utilising good tool support.
It also pays to utilise a tool support system because you can in some cases, reduce the overall length of your tools because with good tool support, you might need less shank length in the collet to clamp on which means a shorter blank for the same fluted length, so you get valuable saving on your raw carbide costs.
So give your tools the support they need, so you can crank up your profits by increasing your feedrates at the same time that you are improving the quality of your finished carbide tools.