The holes is smaller than CAD file

I printed a small part,but I found the holes is smaller than CAD data,the hole of CAD is 12.1mm,the printed part is 11.5-11.6mm,how to improve it?

Use the offset. Make a small test block with a few holes of different sizes. Try puttin .1 in the “holes offset”. Keep changing value until you get it.

Once the correct offset is found, does it stay constant for all prints thereafter, or do you have to re-calibrate it for different prints? If it's constant for all printers and all materials and all prints then why is a compensation adjustment required? What parameter is it that varies, requiring compensation?

You can use it as standard for all your prints (depending on the fit you need) in M200 printers you can choose .12mm for fixed interlocking parts, and up to .2 for fitting mobile parts.

I've been doing trial and error printing of BraBeast parts from Thingiverse and finding that some parts with holes need about 0.10 to 0.20 mm contour offset for mating parts with pins to fit together well enough for the pinned part to rotate with respect to the hole in it's mating part.  It would be nice if an outer contour offset could be assigned a negative value to give it a smaller than designed OD.

http://www.thingiverse.com/thing:48087

Mike

Once the correct offset is found, does it stay constant for all prints thereafter, or do you have to re-calibrate it for different prints? If it's constant for all printers and all materials and all prints then why is a compensation adjustment required? What parameter is it that varies, requiring compensation?

I haven't had much luck with this adjustment. I can fine tune the ID, but then the outer always changes as well. Then switch colors, or to z-ultabs gets to be to time consuming trying to chase accuracy as each filament prints slightly differently. Especially with how long it takes to just print small test parts. I recently printed a small injection mold for silicone overmold on top of another printed part. I couldn't even imagine how much time and material I could have wasted to get all this parts to work correctly right off the printer. Use extra walls, drill and sand to fit. I start with 0 or small, and tune it post process. 

If I only printed one color all the time, then it would probably be worth my time to dial it in. I started a taking a few logs to dial it in, and each adjustment effected the other, and you can start chasing your tail real quick when both ID and OD are critical. 

The Up produces ID's consistently on the small side by approx 0.5mm - I just drill them out if needed, which results in a better hole anyway.

I've found 0.03 and 0.16 for outter and inner contours respectively makes   the best accurate parts. Have tried for several ones but it might change from printer to printer...

I have done now some 20 prints and the difference between drawing and print is at a total length for example of 60 mm some 0.88 mm in the Z direction and 1.14 mm in the X direction.( in the dimension elite the same part has in both directions Z= 0.23 mm more then designed and in the x direction 0.19 mm). Now printing a T profile Grove and the T to fit in, then you get really in troubles. Here i have at 5 mm design measure 0.34mm off and in the grove i am 0.2 mm to small so it does not fit at all; additionally small T bars on top of the block peel off at the connection area and don't hold. How can i get this fixed? 

In general the big flat areas have excellent quality although at 3.5 cm height the deviation in the 90 degree angle is 0.3 mm and the 4x90 degree angles are not really 90 degrees its always a bit out of the 90 degrees in all directions.( in dimension elite not a problem so far) You don't see it if it has not to fit in a frame but for technical prints a bit problematic. The connection areas to the supports are really messy and not very handy to clean and repair.( even with sanding and with hot air not easy to repair).

If with offset correction fitting, is the setting then for all future parts the same or depending on filling grade and size of the part to fiddle again to the correct setting? Sofar trustworthy and fitting parts are only flat and with big tolerance holes for closing lids in boxes etc. but not for exact and precise parts. If there is a setting which would correct all those inexact outcomes i would love to know.

thanks in advance

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Nikolaus, please upload files I make a test print. BTW try changing orientation of part for that particular one you might want to try printing T on Xy. Always print critical part on xy and use offset several users report values ranging from 0.1 to 0.2 for holes and somewhere 0.01 to 0.05 for outer.

Hi, I got my M200 a couple of weeks & do love it :) but I did a 21 hour print, only to discover afterwards that most holes were too small in diameter. Holes ranging from 3 to 12mm diameter were about 0.2 to 0.4mm too big respectively.

I assume that one offset setting is for the whole print, so I'll have to use an average offset value or prioritise which holes need to be more accurate than others.  Would a percentage offset setting be more appropriate_?

21 hours is a lot of effort to tweak & optimise the offset value, so (longer term) can this be pre-calculated in future Z-Suite versions, because it seems as though its a known issue with quantifiable offset values for other users_?

Similarly, with some simple Test/Calibration models from thingyverse, my M200 consistently makes the square and round holes too small (by an unknown % factor, to me), so why can't this be relatively easily pre-calculated in Z-Suite_?

Apologies in advance for my naiveness & ignorance :)

My holes are ~0.010" (.254mm) under-sized, for both my machines.

And that seems to be regardless of color or material type.

I've found the Z-Axis part dimensions to be the least accurate, sometimes off by as much as 0.015" (.381mm).

In general, the M200 is pretty darn accurate, but it could be better.

(my friend and I compared part accuracy w/ his Ultimaker 2 and he seemed to best the M200 by only a few thousandths, but that was only 1 test)

I'd like to see Zortrax spend the time doing a case-study of part accuracy.

Then after enough case-studies, they could dial-in the correct compensation to get some consistent results across the board.

*regardless of how many different variables are at play here, it is still possible to test and compensate. It's just a matter of doing enough tests.

Caliper is not best tool for accurate measurements of holes, mostly it measure with 0.05-0.1mm smaller diameter than it is and if it is about plastic which can compress then anything can be measured.

Here is what happen when Julia and YosemiteSam try to measure hole in precise part using caliper

http://forum.zortrax.com/index.php?/topic/1444-aftermarket-nozzle/#entry19579

 

I'd like to see Zortrax spend the time doing a case-study of part accuracy.

Then after enough case-studies, they could dial-in the correct compensation to get some consistent results across the board.

*regardless of how many different variables are at play here, it is still possible to test and compensate. It’s just a matter of doing enough tests.

We always want to do this but caliper and common measuring tools give no serious data for it, we just received CMM system which should help to create full documentation.

Best Regards

Martin

I always do the holes in the design 0.15mm larger un diameter than what I need

We always want to do this but caliper and common measuring tools give no serious data for it, we just received CMM system which should help to create full documentation.

Best Regards

Martin

Martin,

Gage pins or hole gauges are less expensive ways to measure hole diameter than a Coordinate Measuring Machine and would make good bench tools in the QA lab.

http://www.amazon.com/s/ref=nb_sb_noss_1?url=search-alias%3Daps&field-keywords=gage+pins

http://www.amazon.com/s/ref=nb_sb_noss_2?url=search-alias%3Daps&field-keywords=hole+gage&rh=i%3Aaps%2Ck%3Ahole+gage

From what I've seen, most holes in 3D parts are actually polygonal in shape, rather than true circles.  If that's generally true, it may be hard to define, much less measure the hole diameter.  Do you define it as the distance between two opposing facets or two opposing pairs of vertices?

Mike

I get a lot of round parts to print for customers.  

IMG_1524.jpg

Martin,

 

Gage pins or hole gauges are less expensive ways to measure hole diameter than a Coordinate Measuring Machine and would make good bench tools in the QA lab.

 

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I actually used gauge pins but CMM give possibility to measure hole roundness error and surface flatness deviations plus it looks and works cool when I can pick up any feature from CAD model and get measurement with displayed deviations :wink:

And it is true with holes there is small inconsistency, compensation for XY direction changes will help with holes a lot but we still testing this feature.

Best Regards

Martin

Hi,

that's great news that you've invested in a CMM :) and that you're conducting tests to deal with the "manual offset" issue.

When do you expect to update the software &/or firmware to fix it, such that a "manual offset" isn't needed please_?

PS. "manual offset" would still be a nice option to have :), but the M200 should pass Test prints without having to use it I think :)

regards

Conrad