News Technology

When you're chasing microns, there are no shortcuts.

I thought I'd get the gist of this article out of the way at the beginning. Despite the enormous advances in technology that helps a CNC machine operator in all sorts of ways, the reality is that you really need to do every step of the process correctly to ensure you achieve the result you want.

It's about planning, making certain that your equipment is in top condition and spending the time needed to limit the chance of errors. If you're just grinding a small batch of ten tools out of carbide and you have to scrap three—that's some serious money coming straight off your bottom line.  

So, I want to look at a few of the areas you need to watch out for and discuss how technology can help you get it right. Right from the first tool.

There's no substitute for experience.

Way back in the day, when I was first selling CNC tool grinding machines, a lot of operators coming from using manual grinders were wary of this new tech. They weren't sure they could deal with the transition to computer-controlled CNC machines. I'd tell them, I'd much rather have someone who understands cutting tool geometry and learn how to use the software and CNC grinding machine, rather than someone who's comfortable with computers trying to learn how to grind cutting tools.
 
The same is true today. All the technology we put into ANCA machines is really just a way to help good operators perform more efficiently and with even higher precision. But what it can also do is really reduce the likelihood of messing up a tool. Let's see how.

A virtual rehearsal.

ANCA's 3D CIMulator software simulates the programmed tool path exactly as it would be ground on the machine. The easy-to-use interface is highly intuitive and lets the operator see an exact 3D model of the tool being designed. Moving through the process is simple, thanks to wizards that ask a few questions about size, length, diameter, number of flutes, and so on to set up the basics before specifics need to be inputted. Help pages are available at every step, so anyone can become familiar with the system in next to no time.
The software takes care of a lot of the work by automatically calculating collisions that may occur before grinding and when the machine configuration is changed. CIM3D can also calculate the material removal rate and how to balance a tool. It simplifies workflow, saves time, and reduces the chance of missing collisions and making mistakes.

Be prepared for blank prep.

As with every step in the process, preparing the blank is all about attention to detail. You can't expect to grind an accurate cutting tool if you haven't ensured the blank is accurate too. The steps or diameters on the blank need to be ground to very tight tolerances—in some cases to within a few microns. And then the blank needs to be accurately set within the tool holder and method of support. Doing all of these steps precisely is critical to a successful outcome.

Grinding wheels.

Accuracy is of paramount importance when it comes to your grinding wheels too. Diameter, width, shape, and length from the spindle face all need to be spot on. And, naturally, it's vital that the wheels are conditioned, trued, and dressed correctly.

ANCA machines offer automatic measurement and qualification of the wheel pack inside the machine. Using iGrind, the operator can choose what aspects of the wheel pack to qualify before triggering the qualification cycle. Before the wheels are digitised, the probe itself is re-qualified using a qualification block attached to the spindle housing.
   
The tyranny of temperature.

Another important factor to consider is temperature. Both the ambient temperature of the machine shop and the temperature of the coolant inside the machine are critical. The slightest fluctuation in these can have a significant effect on the job you're doing.

Fortunately, ANCA has come up with an innovation that really helps. The Motor Temperature Control  system (MTC) actively manages and maintains spindle motor temperature, regardless of operating conditions, by modulating the motor operating efficiency. It improves dimensional stability and reduces the warmup time required by the machine. In addition, ANCA's Launch Pad software enables you to warm up the machine for, say, half an hour before the start of a shift so it's ready to go when the operator arrives.

It's also important that your coolant stays clean. If you don’t have a coolant filtration system that removes the swarf to high filtration levels, the dirty coolant could affect the finished part and surface finish on the tool. Plus, it's likely to reduce the life of the grinding wheel because you'll have to dress it more often.

Words to live by.

As I said, there really are no shortcuts when you're dealing with tolerances this small. Essentially, it's about planning and discipline. Take the time to do every step of the process correctly, and you'll end up saving time and money in the end. The old adage—measure twice, cut once should be framed on the wall of every machine shop.
 

16 February 2022