Some Small Issues with new DMU 60 eVo Linear

[xirdneh1234]

Two months ago we received a DMU 60 eVo machine. It is brand new, with a Siemens 840D and all the other bells and whistles.

 

Been a good machine so far with the exception of one thing. Our Blum Tool Measurement Laser has been problematic. It is built onto a mount on the machine that rotates it up and down. I am seeing measurement variances by up to .07mm (.0027") on length, and similar amounts on radius/diameter measurements. The measurements have been taken from a cold start, post spindle warm-up, and after running 2-3 parts with 8-20 minute cycle times. I was also concerned that coolant mist inside the cabinet may be interfering so I turned off TSC but honestly, there wasn't even that much mist to begin with. Anyway, that didn't change anything, same results.

 

The Renishaw OMP-60 probe is repeating on measurements within .004 mm. This makes me hopeful that I do not have an issue with my drives/scales/axes (at least I hope). 

 

My next test is to use the OMP-60 probe and take measurements of the Blum laser itself (Z axis hit on the top, XY on the side) and record it as an offset, and take this measurement 2-3 times a day for a week and look for any variation that might correspond to the TLO shifts I am getting.

 

Any thoughts on this? Has anyone experienced similar issues? Am I asking too much of the laser?

 

I hope not as I've had Okuma's, and HAAS machines with Renishaw probing systems give waaaay better results than what I am currently seeing.

 

As is, I just cut the first part, and comp the tools manually. This is a PITA as I do prototype work with pretty tight deadlines so I would prefer not having to automatically scrap out my first part due to a crappy measurement on my tools. 

 

DMG Mori support is aware of the issue but they have not found a solution other than suggesting alternative cycles (we've tried them all at this point). They have been fine to work with, but it's clear that they are overworked and stretched too thin, which is why I'm starting to investigate this myself. They are still pursuing the issue, but I am becoming impatient.

 

Any insight or ideas would be appreciated. Thank you.

[Bob W.]

I had the same issues on my Makino HMCs.  I tried and tried to fix it and never could get it right (better than .0015").  Ended up buying a tool presetter (Speroni) and never looked back.  Tools repeat to .0002" and it doesn't matter if the machine is warm or cold, tool setting is completely independent AND doesn't take machine time.  I do use my lasers for break checking though.

[Machineguy]

Something is loose, or you have a chip(s) at the stop position.

Seen it before on a Mazak. It was repaired, but the service forgot to tighten the bolts.

[Matthew Hajicek - Singularity]

My previous shop had a Blum tool measurement laser.  We couldn't get it better than about .002", and it wasn't on a moving arm.  Since they trigger at the point where a certain percentage of the beam is obscured, tool measurement lasers are affected by coolant drops on the tool, and will behave differently for tools of different sizes and with different coatings.  We gave up on using it.

[Mjölnir]

our hermles and ingersoll have blum lasers and we're not having any problems with them. are easily within 5 microns on all three machines. i question the longevity of the lasers on the hermle's though, they're mounted on the back of the trunnion in the machining environment. on the ingersoll the laser is mounted safely behind the tool magazine door.

[xirdneh1234]

Thanks for the replies guys. I think I might go the route that Bob suggested, but will have to wait a bit. A bit outside of the budget at the moment and I need some other items. I think the presetter makes more sense long term and especially as we add more machines to the shop.

 

I'll keep pushing the DMG Mori guys, but if we can't turn up anything else I guess I'm back to just comping tools manually until I can push a presetter through purchasing.

 

Thanks again everyone.

[Gracjan aka Pullo]

I have a Blum on a DMG DMU 60 , I simply cannot trust that thing. I know a company here that bought a DMU65 in May and they asked for a mechanical measuring solution. Worst ever use of 10.000 euros. I can only use it for drills. I have been monitoring that that thing now for like 8 yrs, but basically under ideal conditions repeatability is about 0.02-0.03 mm.  For mold work that is not enough. With a 0.05 steel tape between the tool and the workpiece  get repeatability about 0.002-.005 mm . 

 

 

GRacjan

[xirdneh1234]

Thank you for the input GRacjan. Sounds exactly like my problem. Busted out the Mitutoyo height gauge, some 1-2-3's and made myself a pre-setter for the time being. 

[christopley834]

@xirdneh1234

Hi, we have the same issue with our DMG160FD, did you get a resolve from DMG Mori? We are getting up to .05mm errors on milling tools, we even get errors using the calibration tool this can wander up to .02mm! All our other Blum tool setters repeat to .002mm

[Guest]

all tools or just some? 

[christopley834]

All of the milling tools, turning tools are reading ok using the Renishaw touch probe.

 

[Guest]

With Blum laser measurement systems, I have noticed that you have to use the correct cycle based on tool type to get the numbers right, also calibration needs to be good (calibrated with a test bar as opposed to measured with an optical comparator). Lasers are also suseptible to errant measurements due to high polish cutting tools, the RPM at which the measurement takes place can have an effect as well. I usually measure my tools at the high end of the scale to make sure spindle pre-load is engaged. 

Just some thoughts.

[HEED]

We have a DMU65 with similar issues.  From one touchoff to the next, the tool offset will change up to .003 on a standard .118 drill.  Are your lasers hooked to the back of the trunion, or with the duoblock, I am not sure where the laser is with that setup, but it's kind of rediciulous to have that sort of variance on a laser.  On a machine with scales.  

 

We have had Z ballscrew replaced, machine moved, and isolation pad poured.  Tech from Germany came in and sprechen sie deutsch to it, and no one can get it to repeat any better.

[christopley834]

Thanks for the replies, our laser is mounted in a housing bolted to the side of the table. It lifts up with a pneumatic cylinder on a linear guide. We have been testing the repeatability with our calibration tool this is a ground pin with a known length and diameter (129.999mm L 10.001mm dia) we get errors on that of up to .050mm. 

We have checked backlash and positions of X,Y,Z these are all repeating and reading good we could not find any backlash. The laser comes up to same position and this repeats each time we checked that using a slip gauge and .002mm clock on the spindle so we are quiet happy with the machine positionally. Next we are going to service the laser, clean the shutters and optics, replace the pipework and change the Blum air filters and see if we have any improvements. We have also looked at the spindle RPM this is set to 3000 on the calibration cycle.

We have 8 of these on each of our DMG machines and we have no issues with any others! 

[pullo]

I have been slowly taking parts off my 10 000 e Blum and finally made it repeatable and has the 0.005 mm accuracy I am looking for.  I took off all the stuff in front of the lenses and now it works fine.  Before I measure anything I touch  up the lenses with tissue paper.  I have been running it like that for 3 months now.

 

Gracjan

[crazy^millman]

On 7/22/2017 at 2:09 AM, pullo said:

I have been slowly taking parts off my 10 000 e Blum and finally made it repeatable and has the 0.005 mm accuracy I am looking for.  I took off all the stuff in front of the lenses and now it works fine.  Before I measure anything I touch  up the lenses with tissue paper.  I have been running it like that for 3 months now.

 

Gracjan

Use a coffee filter they are lint free and the best for optics.

[pullo]

OK , thanx , will do that.

 

Gracjan

[Bachmakinoman]

On 11/6/2016 at 8:21 PM, xirdneh1234 said:

Any thoughts on this? Has anyone experienced similar issues? Am I asking too much of the laser?

:HEADSCRATCH: that's a lot.

 

:THIS IS MY GRACE FACE:

[Bachmakinoman]

Did you get it sorted out?

[: Chip :]

Those the same lasers they use in NHRA? 

 

:CHIP:

[: Chip :]

I've run a Blum before. Truth is if your parts are REAL CRITICAL. Your gonna want to take the error out.

i noticed variations after running 15k+ rpm for hours.

Refrigeration is an issue. HSK or taper might vary some.

I had to learn how to adjust for this TOO

Keeping the probes calibrated takes time

:CHIP:

[Leon82]

Our yasda has a big dashawa camera system for tool length measurement. It has been very consistent.

It is usually within 50 millionths or less. Probably takes a little longer than a laser to measure tool though

 

It also has a flat checker option where it will run the spindle and check the length before machining. 

[christopley834]

Thank you for all the responses, we have now got the laser repeating to .003 and we are very happy with that. We replaces the air lines and filters and serviced the shutters this seems to have done the trick. A good tip was to remove the optic guards and run the laser without them this confirmed to us the Laser was working ok and the pribpem must be with the shutters. Once these were cleaned up and put back on it was working fine. 

The reason we replaced the airlines was due to them going brittle, this was our coolant causing this! Has anyone else had any issues with Blaser or Houghtons coolant? 

[pullo]

That is what I suspected too  . Before I removed everything off my Blum  I would clean the lenses and within three, four days  the laser would stop working like totally . 

I will also  thinking of ordering a new active carbon or whatever is in it  and putting alcohol downstream to clean possible oil from the air tubes.  

All my  tubing is nice and perky . I use Swisscool.

 

Gracjan