"I am currently using a particular insert; Is there a better option to use on xxx stainless steel?"
This is an example of a typical question we get asked by customers. Before we can give options, we need to find out why the insert that they’re using may not be providing the desired outcomes for the customer. To give the best advice we need the specifics as to why they think you need a different grade option. We often need to ask,
What are the issues you’re facing?
Is there excess edge wear, breakage, or deformation of the insert?
Any data on feed rate used and surface speeds etc is also information that can influence the insert that we may recommend.
A common reply is that “we are getting breakage of the tips no matter what speeds and feeds we use.”
For us, this rings alarm bells, and usually it has nothing to do with the manufacturer, grade or geometry of insert used. There is generally, no poor quality carbide on the market; often something can be mis-applied, but usually there are under-lying issues.
CNC machines are often taken for granted. There is sometimes, an assumption that “oh it’s a CNC machine so it must be right?” Wrong! We regularly see instances of machines being out of alignment; sometimes by only a small amount, but this can have a massive impact on tool life and performance. The situation becomes more and more crucial as the components reduce in diameter.
For example, CNC turning (lathes): No cutting tool will perform correctly if the cutting edge is presented inaccurately to the workpiece. If the tool centre height is above or below centreline, it simply will not perform as the manufacturers intend, whether external turning, internal turning (boring), drilling, use of multi-function tools, rotary broaching, slotting etc.
Often, there are tell-tale signs that all is not well other than poor tool life:
- If a pip remains when face turning to centre (indicating a below centre situation)
- An external / convex lump remains when facing to centre (indicating an above centre error)
- Uneven body wear when indexable insert drilling (there should not be any visible tool body wear when drilling)
Unfortunately, there aren’t many tools that are available on the market that allow for out of centre adjustment. To ensure your inserts have minimal damage and to stop breakages of tips the main piece of advice we can give is to make sure you maintain your machinery properly and don’t wait for a problem to occur. Machine tools are often overlooked, most people have their car serviced regularly; why would you not do the same for your machinery?