Ldo Voron frame QC issues

[SamppaD]

Hi. Has anyone come a cross warped LDO frames? I purchased mine from authorized seller from Germany,that frame had a 6 warped extrusions and some of the vertical A extrusions were cut to short. Contacted seller and they contacted LDO. LDO shipped 6 new A extrusions but shipped extrusions were wrong length.Well LDO send a new frame and this new frame is worse then old one. So my question is, is there a frame seller that actually sell a straight extrusions for Voron 2.4R2?

Edited July 30, 2023 by SamppaD

[Simon2.4]

Yah, extrusions have very poor tolerances, however, the cuts should be accurate to 0.001" there's no excuse for that. A possible solution could be to use shims to make up for the inaccuracies.

[SamppaD]

Yes,that a possibility,asked ldo if they have spacers,like basically cut from a 2020 profile to a specific thickness but no. If i put some standard shims ,it looks bad. There shouldn't be needed for customer to purchase what is supposed to be a quality frame  and then take that frame to cnc shop, machine it to tolerances what is expected and replace warped extrusions on top of that. If I'm lucky i can fix my original frame with the parts from new kit that are good. In new kit I have  4 A extrusions and 1 B that are perfect the rest is out of specs or warped. Old frame is at my desk on a granite desktop that is machined to a tight tolerances,and i need to start measuring that frame and replace individual extrusions. I lost weeks waiting for a replacement parts, and then a new frame came with poor tolerances ending in this situation.

Edited July 30, 2023 by SamppaD

[claudermilk]

So far I've only used a 250 Trident LDO frame kit, but that was excellent quality and has zero issues. I have a V0.2 kit sitting here that I haven't gotten to yet. I'll take a careful look, but I don't anticipate any issues.

Maybe bring the issue to Jason's attention on the Voron Discord.

[VoronManiac]

No excuse for extrusions of differing lengths with square ends.  Doesn't help you directly but the Formbot 2.4-350 kits were spot on measured with some 600mm calipers (weapon).

However.  There was measurable bowing (not twisting) of the 2020 extrusions especially the X and Y.

One thing I discovered was even if you started with a perfectly straight extrusion, the linear rail / 2020 extrusion will bow when attached together even with very modest torque on the M3 screws. This makes sense if you think about it because the aluminum is getting sandwiched.  Also recall the TAP video where a series of bumps were showing up in the bed contour map that corresponded to the points where screws were attached to the linear rails.  The FIX was to pre-stress/bow the  2020/linear rail with some aluminum foil shims as the screws were tightened,  With a small amount of iteration, assembly was "perfectly" straight after all the screws were tightened and the stress was released.  Back lit the 2020 with a flashlight on a quartz counter top to see bowing/gaps.  Order of tightening the screws also makes a difference.  I expect the normal warping when the chamber heats up, but is should be no worse if the assemblies are pre-stressed. 

[SamppaD]

Hi. Thats correct,however my extrusions are twisted and cut to wrong length. When frame was assembled it was torqued to 4Nm (M5 bolts) with a torque wrench on a granite tabletop that was machined to a tight tolerances for this job,so in that way all bolts are under same stress. I will try to find time for messing with a frame on saturday. If im lucky 4 A extrusions and 1B will be sufficient to repair this frame. Based on my measuring most of the issues comes from A extrusions.   Do you have that tap video link,i would like to see it? 

[SamppaD]

Latest update for LDO tolerances is 0,2mm ,not a 0.001" this is confirmed by Jason from LDO. Now i will measure all extrusions from 2 kits and with a little luck build a frame that is square. Lets see how it goes  

Edited July 30, 2023 by SamppaD
Updated to latest info

[SamppaD]

Update on frame build. After some wiggling with the frame, measuring all extrusions from 2 kits and 6 replacement extrusions and taking only the matching extrusions with same length,and no warping build a frame that was off by 2mm. After measuring the frame again swapped few A extrusions position in the frame..end result is a frame that is square, all corners are 90 degree,cross measurement is spot on. I have however extrusion bowing that was measured  frame flipped on one specific side and rotated 90 degree and then 180 degree  at 2 corners measured  0,15mm and 0,5mm, everything else is spot on. I think it good to go with the build. Its with in the LDO and Voron specs,good for them ,its good for me.  

[Simon2.4]

On 7/29/2023 at 6:55 AM, SamppaD said:

LDO tolerances is 0,2mm

0.008" ... It will work fine but meh. That's accuracy I would expect from cutting with a miter saw. I ordered some cut extrusions from Misumi and they were all within .001 of the ordered dimension; though some were twisted and bowed too.

[SamppaD]

Hi. I was also surprised with this tolerance that was provided by Jason. I expected nothing less then a perfect cut. Jason provided pdf Misumi  tolerances for extrusion length. Cutting tolerances for Misumi are as high as 0,5mm .  I had 2 LDO frames 300mm build and 6 RMA extrusions . 

What i did I  took all extrusions, separated them in to group of  A -B-C extrusions. I made a setup using 2 875/0 machinist square fixed to a correct distance for A- B-C extrusions on a machined granite surface and compare every extrusion. 

From that setup took only correct size extrusions that are cut to the same length and  without twist or bowing for the build. What i found out is that half of the A extrusions are not acceptable by my  standard. What i expected is that A extrusions are at least the same length and so on. Well after checking all extrusions for length, warping ,twisting issues found out that from 2 frame kits and 6 rma replacement extrusions half extrusions was out of spec for my liking. Luck was on  my side as i had  correct amount of good extrusions that i managed to make a good square frame. As a customer i didn't expected to go try all this hassle,I expected good frame but that was not the case. I had good tools to get this sorted and Jason provided many parts to get this fixed,but many people don't have and they expect that frame is top quality.  Lesson learned hard way,always inspect extrusions before starting build.

 

Misumi_Extrusion_2020_technical_p2_0493 (1).pdf

Edited August 7, 2023 by SamppaD

[Dmandn]

This is concerning when you consider the prices being charged.

....I'm now worried that my LDO frame kit might have issues....

[SamppaD]

Hi. In my case all i can say is that i didnt expect this kind of issue from LDO frame. Measure the frame corners with machinist square, (every corner,top to bottom) you will most likely find some bowing on the corners. This is something that cant be avoided and will not affect printer build. If you measure from corner to corner cross measurement and this value is within 0,5-1mm tolerances then there is no problem with  the frame. Voron frame tolerance is 1-2mm. The best practice is that you measure all extrusions and check for warpped or wrong length extrusions before starting the build. In a perfect world all extrusions should be 100% same length and without warping,only then you can build a perfect frame, however this is not the case. I still think that LDO frame is the best that you can purchase on the market today. Im sure that LDO step up and fixed issues with the extrusions.

[claudermilk]

I doubt this is the norm. A lot of people have built LDO kits without issue. I've now used two LDO kits (Trident frame, and V0.2 currently in progress). My kits have been perfect. They were pretty easy to get all square.

[SamppaD]

Hi.I have 2 frames from LDO, to make one good i needed a new frame and 6 rma extrusions. Basically i had 50% of A extrusions defective with in 2 LDO kits. You were the lucky one,if you got perfect frames. Now if you measure frame using some small square 100mm length then most of the frames are perfect based on that square you are using. If you really want to make sure that your frame is perfect you should use 875/0 machinist square preferably square  need to be at least 200-250mm or more in length.Only then you will notice extrusions possible issues. Lining all extrusions with same length between 2 squares that are locked and adjusted for extrusion length on a flat surface and you might find some extrusions that are 0,2 or less off. Other possibility is to build frame on a perfectly machined flat surface,granite stone for example. Inspecting all extrusions on the stone and pressing from the opposite corners ,then rotating the extrusion to the next side and doing the same thing and so on. I can bet that you will find extrusions that are twisted. This is based on my experience with 2 LDO 300 mm frames,and after talking to Jason from LDO ,tolerances for warping,and cutting are tighter then with misumi frames,however there is no perfect cut 0.0001" and there is always some warping that is within LDO tolerances most of the time. LDO  tolerances for cut is 0,2mm max. LDO is cutting extrusions from a long extrusion bar this can unfortunately make some extrusions warping and possible cutting errors. 0.2mm is good tolerance when compare to misumi 0.5mm tolerances for cutting. It all comes to how well the cut was made from manufacturer side,what kind of surface are you using and how good is your measuring tools. In a perfect situation you would like to cut all A extrusion at the same time this way if you cat them 0,5mm too short or to long its not a problem at all as all extrusions are the same size,but when cutting extrusions from a long bar and you make a mistake then you have a problem. Long story short,as long as frame cross measurement is within spec there is no problems. I like to keep my tolerances as low as possible,this make live easier when building a printer

[7milesup]

I built an LDO Voron 2.4 back in January and did not have any issues.  I should point out that I have a metalworking shop so I do know a thing or two about tolerances.  I find it interesting that we are talking about tolerances of 5 thousands of an inch.  Most folks have absolutely no way of measuring tolerances of that degree and I would suspect that there have been hundreds if not thousands of Vorons built with greater tolerances than that.

[SamppaD]

Hi. As long as parts are with in LDO specs its fine and  will not affect build. When parts are out of specs then manufacturer need to step up and fix the issue. Manufacturing issues are common and good practice is to inspect parts before building any frame.  Anyway this issue has been resolved,and we can all agree that this post can be now closed.

[Simon2.4]

5 hours ago, 7milesup said:

Most folks have absolutely no way of measuring tolerances of that degree

Sad truth.. A few years ago, I was able to grab a 500mm digital caliper. This one by HHIP: https://www.amazon.ca/gp/product/B01BHHFX5G/

That's the instrument behind my claims.