Grinding Moulder Knives with a CNC
A CNC grinder will grind a knife in about the same amount of time as manual grinding, so it's not a production decision. The real benefit is no one has to stand there while the machine grinds. So there is a huge labor savings. Other major benefit is safety... all the grinding is happening in an enclosed cabin.
They aren't cheap, though. Investment is $160k. This works down to $18/hr on 5 yr financing and 1 shift operation. People find that the labor savings justifies the machine at about 8 hours a day of manual grinding. (Meaning if you have 2 machines and they're both used 4 hours per day, you should look into one.)
From contributor K:
I don't know much about CNC grinding, however we have a 75-12 profile grinder from SCM and it works perfect for 2 shift production and has since I have been there, for 3 years.
From contributor J:
One thing to consider when grinding corrugated knives on a CNC grinder is that if it is a machine that picks the knife from a magazine rather than grinding in the head, it is going to reference the profile off one edge and off the back of the knife. The head references off the corrugations. Bar stock is not necessarily ground perfectly along the back edge, so you will always have problems with one knife doing all of the work. It is not the way to go for high-feed applications. If your CNC machine grinds the knives in the head, it is a good way to go.
From contributor D:
Contributor J makes a good point. The P20CNC machine grinds the knives in the moulder head or in a dummy head that references off the corrugations. Pick and place autoloading is not the most accurate way to grind corrugated knives.
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