tnc 426 hied

[mrmead]

anyone know how to change the backlash on the hiedenhien controls any help would be great thanks

[G Caputo]

Isn't backlash a machine charecteristic such as a worn ball screw, loose gibs, etc. and not a control issue? Perhaps I am not understanding what you are looking for. If I can get myself on the same page as you, I'll see if I can come up with anything.

[Hardmill]

It can be comped in the parameters. Try a search mrmead.

 

 

PEACE

[G Caputo]

Hardmill,

My bad, you are right. I found it in the book. I'll see if I can find it online before I type it out.

[Guest CNC Apps Guy 1]

Yeah it's in there with your Pitch Error comps.

[G Caputo]

Positive backash: rotary encoder advanced relative to the table (traverse movement of the table is too short)

 

Negative backlash :rotary encoder retarded relative to the table (traverse movement of the table is too long)

 

For every direction reversal the TNC subtracts or adds the value from the machine parameter MP710.x to the value resulting from the encoder signals

 

MP710.0-8 Backlash compensation

Input: -1.0000 to +1.0000 (mm) or (degree)

 

HTH

[Rick Henrickson The Boeing Co.]

how did you check your backlash?

[Zoober]

With a backlash-ometer

[Rick Henrickson The Boeing Co.]

oh robert you funny

[Guest CNC Apps Guy 1]

I check it with a .00005" Indicator. In the past I've used Masters. Measure the first location, zero your indicator, move by MDI programmed move, move back and measure that difference. That is your backlash. Also, when you're jogging by handle; is a .0001 move shown as a .0001 move, BOTH directions> It should be if you have you indicator set properly and if your machine is dialed in.

[Zoober]

Be careful about using the indicator to judge whether the table moved .0001, as there can be sine error in the indicator if not set up right.

 

As the Miyano factory trained us, always judge backlash as the repeat positioning BACK TO ZERO from each change in direction move and back.

Also, be careful on using very small movements (under .010), as you have stick/slip involved, 'specially on older machines, and can show as backlash, when it does not exist on say a 1/2" move.

Also, many machines will have backlash adjustments at various positions of the table/head, and you may need to go back and forth, as one change may affect another.

Always verify after making changes.

[darren]

Also there is backlash paramaters for G00 and G01 moves so you need to always use either g00 or g01 in yor MDI program to obtain correct backlash settings. I set using a dial indicator likeJames machine a circle (dia 100) and do 3 dia 12 bored holes in a triangle 150mm apart. Then i get it checked on our CMM.

[Guest CNC Apps Guy 1]

quote:

---

...Be careful about using the indicator to judge whether the table moved .0001, as there can be sine error in the indicator if not set up right...

---

+1,000,000

[mrmead]

thanks everyone for the info im looking into it now thanks again

[Watcher]

I believe that the most reliable tool to measure machine geometric errors with precision and efficacy is a Ballbar device. This tool is able to inform you where, how big and how to fix these kind of erros.

 

JM2C

[mrmead]

we used the ballbar test and we changed the backlash with success thanks for everyones input now we have 1 more happy operater

[Rick Henrickson The Boeing Co.]

I was under the impresion that pitch error comp and backlash were measured with lazer,

+1000 on back lash I was told to program 1" out then 1" back then 2 out and back, 3 out and back etc.