There is an age old saying that’s goes, “Do it once. Do it right”. This holds true for production grinding too. You can save valuable time and money by taking a few minutes to set up and tune your carbide tool grinding process. A modern CNC tool and cutter grinder will have the capability to be finely tuned to maximise the efficiency of your production runs.
Optimisation begins with good set-up. We’ve already discussed the physical aspects of setting up your tool grinder for carbide tool production - the importance of good wheel selection, coolant quality and flow, and the benefits of tool support.
But what about the setup of the programs that will run your batch? A huge time waster can be configuring the software of your CNC tool grinder to actually grind exactly what you want to produce.
The software installed on the CNC of your modern tool grinder should have user friendly screens to guide you through the set-up process. If you are grinding very complex or unusual tools, you might need to ensure your CNC is running high end or specialist software options that help you to easily configure the geometry of these tools or you could waste hours or even days, trying to set up a tool that the software was never designed to cater for.
One very effective way to quickly prove out a new tool design that could save you a big chunk of non-production down-time on your machine is “Dry Run” mode.
When you have entered all the data describing your tool and the grinding cycles you want to run, switch on your CNC’s “dry run” mode and give the cycle a quick run through to check that all the machine motion looks reasonable.
Better yet, perform your dry run using your CNC’s MPG feed feature if it has one. This ingenious invention lets you prove out a complete tool program by simply winding the hand-wheel.
This leaves you in complete control at all times and eliminates any surprises you might otherwise get if you accidentally put the decimal point in the wrong place for one of your parameters!
Dry running your program is effective and can save you lots of time and scrap tools, but by far the best time saving you can get for program setup is to go “offline”. Invest in a PC loaded with an identical copy of your CNC’s software and preferably 3D simulation software for the grinding process. You can then setup your next tool while the machine is busy producing the current batch.
3D simulation has revolutionised the CNC tool grinding industry and if you don’t have it in your shop, you will be losing out big time to your competitors who are using it.
With 3D simulation, you can see exactly how the tool will look like and verify and measure the actual geometry, then make as many design changes you like, all without interrupting your machine tool from its very important job of making money for you.
As well as selecting efficient spindle speeds and feedrates, there are other simple things you can do to maximise your production rates - some as simple as flicking a switch.
The first thing to do is to switch on adaptive feedrate control on your CNC if it supports this feature. Adaptive control will alter the feedrate depending on the spindle load so you can go faster over the shallow cuts and the CNC will automatically slow the feedrate down during deep cuts. This translates immediately into faster grind times and maximum use of your expensive machine. Before switching on adaptive control, you should check your wheel specs first. Some wheels, such as hybrid bond diamond wheels, must be loaded up aggressively to keep them sharp.
It also pays to experiment. By monitoring the spindle load meter, you will sometimes find that you can lower the spindle speed and increase the feedrate for an aggressive cycle time improvement.
Remember, the bigger the batch or the more times you anticipate running the same batch, the more it pays to spend some time in optimising your process. You can even get to the point of optimising the distance of approach, retract and gap movements between cycles to reduce cycle times, although you will find that on current releases of modern tool and cutter grinder software, that the software is often smart enough to make these adjustments for you automatically so your machine spends more time cutting metal and less time unproductively grinding fresh air.
Remember, each optimisation you make can be automatically reapplied the next time you run the same batch so it’s definitely time well spent, and when setting up: “Do it once. Do it right!”