Machine Geometry Verification Part

[Watcher]

Hi everyone!

 

We are trying to get rid of some problems with our DMG machines. One of them is the poor repeatability due to thermal/mechanical drawbacks in the machine project. We have 18 DMU70Evolution here and all them suffers with the lack of accuracy for 5 axis 3+2 machining. We want to develop a verification part to machine in these machines, inspect this part and check the machine accuracy, so that we can release the machine for production or not.

Another common problems is when DMG service releases the machine and we do not perform a machining test to make sure that the service solved the issues.

That said, I´d like to ask your if some of you could share a interesting model that we could use to test machine geometry.

 

Any commnents regarding these difficulties I described here and any idea to solve them will be greatly appreciated as well.

 

Thank is advance,

[gcode]

A four sided pyriamid with a flat top and

a precision hole in the top face and all 4 angled

faces is a common test.. I don't have a model though.

[cobra95kev]

Check out the file linked on this page as:

 

cds5.stp

 

HTH

 

EDIT:

I guess it would help if I pasted the link.

 

http://www.isd.mel.nist.gov/projects/stepn...-2005/index.htm

[Colin Gilchrist]

Nice link Kevin!

 

If you read a little farther down there is also a circle-diamond-square-cone part under the everthing.stp link. I think the NAS979_NIST.stp file is a half-size version which might also be of use...

[X-L Engineering Corp]

Vary helpfull but I tried to open those files and they were only text files I coildn't open them as stp files.

These would be helpful for me we are going thru Machine Validation and Process Validation with ppap studies right now. Another help would be appreciated.

 

I remember I believe in V9 that to setup the Machines it was necessary to cut a cycle and then blue it up then continue to increase the feed rate until it went out of round to determine the max feed rate for the Machine. Does anybody still do this?

 

Thanks in advance for any suggestions.

 

Ted

[X-L Engineering Corp]

Bump+

[ak762]

Just check to load Everything.stp really after save it came as Everything.stp.txt

renamed it and opened in Solidworks

all appeared as solid assy

[Reverend Turk]

off topic but ak...your signature disturbs me!

[X-L Engineering Corp]

Thanks for the help

 

Turk

The question is witch one is he in the picture?

LOL

[Steve Hattori]

Watcher, if you have the Heidenhain control, there should be a geometry file for checking 5x positioning yourself. We have a Hermle, and the file is called "Zyklus 19"- it checks the postioning at A + and _ 90, with C0,90,180,270 and prints a file. You can then change params to get it straight. Ours is a trunnion-table type, but I have seen DMG guys use a similar cycle for doing the nutating-head machines..

[JG]

Hi Watcher,

 

I don't know if this will help you or not but we had a DMG 125U (head/table) with a siemens control that was deadly accurate, when installed there was a kinematic routine that was run using the probe and a sphere mounted on the table, the program ran and updated the variables used by TRAORI. after running that program I put a tenths indicator on the sphere and was able to move anywhere in the travel limits (linear and/or rotary) and did not see the indicator move. You should check the doc's and see if you have something similar (all of this was supplied with the machine) below is a video of a part I was machining (as a demo).

 

note: I did not upload the video, someone else did.

 

thanks,

 

jg

 

http://www.youtube.com/watch?v=tIL-XuBK_-Q

[Watcher]

Hi JG,

 

Thanks for the input. We have also in our machines a DMG optional kit named 3D Quick-Set, I guess we are talking about the same thing. The routine measure the machine kinematics and updates the machine parameters. However it´s not enough in some case. We had some examples here that 1 hour after the calibration the machine lost the precision again. We have 16 machines and the problem happens in most of them. I guess it happens in all machines, however because we do produce certain parts which are not so accurate as other ones, we don´t see the problem in all machines. The problem is critical in the machines producing accurate parts.

Our product is very accurate as well: 0.02mm as true position for a set of multi-sided holes is not a funny joke either...

[JG]

Hi watcher,

 

3d-quick set, thats what it's called, thanks. do your machines have scales on them? (linear and rotary)

 

thanks,

 

jg

[Watcher]

Yes, we have all bells and whistles here, (Collant through - 10 - 20 - 70 bar / Coolant refrigeration / Direct mesurement: linear / rotary, etc) but I think that the thermal compensation algorithms do not work correctly...