What's new
What's new

Multiple Lap cycles needed for roughing and finishing?

clayton

Aluminum
Joined
Aug 19, 2011
Location
Houston Texas
I use G85 cycle for rough turning with a finish pass using two different tools all the time. But if you have a threaded feature with relief behind threads for an o-ring, I don’t want my DNMG tool to gouge that since it doesn’t have the needed relief for a 45 deg chamfer on the back of the threads. The finish tool is a VNMG which has no problem doing that.

What is the appropriate way to program it for the roughing tool to pass over that feature and just leave it for the finishing tool? Is it as simple as defining another NLAP, such as NLAP1 and running a G87,G81? I couldn’t get it to work.

Control is OSP5020L

I use
G85 NLAP
G87 NLAP
Then
NLAP G81

I haven’t ever described a separate roughing profile. It’s probably more simple than I’m making it. But I haven’t figured it out.

Thank you in advance.
 
AFAIK you can't pass over features defined in the NLAP profile.

If you must use the DNMG tool to rough, you'll have to leave the undercut out of the NLAP profile and program a separate finish profile for the VNMG tool that has the undercut. IOW, you can't use G87.
I don't think this is really the best method because taking that undercut in one cut is going to leave an ugly finish that probably won't be suitable for an O-ring.

The other option is to program the entire profile with undercut, use a VNMG rougher with G85 and a VNMG finisher with G87.

Don't forget to use tool tip 8 to avoid overcutting on the trailing edge of the tool.
 
So I figured it out. You can immediately write following the first NLAP G81 with another like this.

G85 NLAP
G87 NLAP
NLAP G81
G87 NLAP2
NLAP2 G81

To be clear on the o-ring feature it’s not a groove it’s a relief behind threads and an o-ring sits against the plug to seal against the face of the mating part. It’s like an oil filler cap plug. Not a shaft with a groove. 45 degree relief at the back of the threads and a small gap then the shoulder of the part.

G1Z0.0X0.F.003
G75X.25L-.03
Z-.3
X.225 A225.
Z-.378
G75X.5L-.01
Z-.5
G0X0.75
G0X20Z20

Simple profile like that for example. Material is aluminum so the amount of material removed is ok and the finish is fine. Later in my program after the threading cycle I redo that back relief to deburr and the part comes out great. The parts are being bar pulled and doing large quantities. So I let the machine do all the deburring so I don’t have to touch a million little parts.
 








 
Back
Top