Newbie- Is this normal? Insanely SLOW machining

[Mark @ JARD,Inc]

Hey all.

Its my virgin thread, so I would appreciate a huge response.

I work for a guy that just bought his first CNC VMC in the form of a 1990 FADAL 4020 with a 88HS pendant.

I programmed a simple face, drill and tap operation and the cycle time is ridiculous.

Firstly, I am using multiple fixture offsets with multiple tooling offsets and everytime I change those offsets, the tool has to travel to the same XY but using the different offset.

There has GOT to be a better way. Somebody post the best method to do this in lamen terms?

Secondly, I thought that the mem scans x-amount of lines ahead in the program so WHY does it take so long to get from point A to point B. My rapids are fine, but it just takes FOREVER for the axis movement to slow down and fiiiiiiiiinnnnnnndddddd the exact XY that it needs.

PLEASE HELP!

[scadvice]

Let us see your program. It will help to figure out what is going on. Show all the prep commands ect but you can delete all but the starting and ending X,Y, & Z numbers if you want in between the rapids, tool changes, offsets, and ect...
Other Ideas:
A parameter may not be correct.
Feed pot? Rapid selection?
G1 where there should be G0's
Something in the program that is making the machine compute or crunch a bunch of numbers.
Steve

[Mark @ JARD,Inc]

Well, I guess I could do that... Give me a chance to copy it over to my laptop...

Can anyone tell me why I keep breaking taps?

Im running a 5-40 into soft steel and c-r-a-w-l-i-n-g at S100.2 (High Spindle) and F2.5... I cant go any slower. Im using a compression holder too...

[jmonty]

Originally Posted by Mark @ JARD,Inc Well, I guess I could do that... Give me a chance to copy it over to my laptop... Can anyone tell me why I keep breaking taps? Im running a 5-40 into soft steel and c-r-a-w-l-i-n-g at S100.2 (High Spindle) and F2.5... I cant go any slower. Im using a compression holder too...

Couple of questions before saying anything...

1. Tap drill size (#39 drill?)
2. Style of tap? 2, 3 or 4 flute, spiral point, spiral flute?
3. Through hole or blind? If blind, how much extra depth are you drilling to give chips a place to go?
4. Coolant, oil or cutting fluid? (Recommend Moly-Dee)

I recently tapped a bunch of the same size holes in stainless steel (17-4ph) @ 300rpm/7.5 ipm using moly-dee instead of coolant & had no problems. In soft steel I would start at 400rpm/10ipm with a good spiral point tap. You can get good quality with lower cost by looking at YG-1 cutting tools (No, I don't sell 'em, I just use 'em.) They may not be as good as some of the premium brands but they don't cost an arm & a leg either.

Slowing down will often cause the material to tear & not cut (you reduce the shearing action of the cutting tool) which puts excessive stress on the tool causing breakage.

If you are using coolant, make sure the concentration is up towards the high end of the manufacturer's recommendation. It should definitely feel slippery with a little body to it when you put some on you fingers & rub them together (not scientific but if you don't have a refractometer handy it works.)

Hope this helps. Good luck!

[Joe Engel]

Check your "XYZ RAMP" parameter for slowing down before finshing the rapid move.
Also the "G0 Detail" parameter for look ahead.
A big plus is to let others look at the program and parameters. Try to post them both. You may get quicker answers instead of questions.

[little bubba]

A few things with the info you gave. What format are you running? format 1 does some wierd stuff with coming back to zeroes.

On the tapping, I would not be forcing it into high gear.

One thing that I ran into last week, and it may be worth checking. My feeds went way off, not good for tapping. The feed pot at zero percent all of a sudden didn't stop the feed, it just slowed it slightly, it was still well over the programmed feed rate though. Feed pot checked out good, power checked out good, swapped the 1090 board with another machine and it worked fine, both machines worked fine, I'm guessing it was some crud.

As for the hunting around for position, could be a G8/G9 problem, or you really need to tune your servos, all that info is in the manuals on how to do it, and the programs should already even be in the controller. Its pretty easy.

One other question, how did a 1990 come with an HS control??

[scadvice]

I thought tapping routine... overrode the feed pot setting? (89 Fadal does).
HS was not available as I remember, but there was a dual processor board that was available a few years later to speed things up. I remember getting a letter about it from Fadal in the early 90's. S##t.... I'm getting old!!
Steve

[little bubba]

Originally Posted by scadvice I thought tapping routine... overrode the feed pot setting?

I thought it did too, apparently it didn't in my instance, but I'm pretty sure it should.

There was something going on that was more than just the feed pot though(I have a feeling something was shorted on the 1090, the cabinet was dirty when I got the machine). At 100% which should have been 38ipm, I was running well over 100ipm, stop watch method, at 0% which should have been stopped, it was still running over 50ipm.

[Edster]

Are you in format 1 or 2?

There is a clock card and a program to check the feedrate. You run the program and it moves the x axis a certain distance and you adjust the card until the time is right. on my iirc its 120 inches and it's supposed to do that in 72 seconds at 100 ipm.