Parts too loose?

Mostly Printed CNC - MPCNC Advice
1

Hello All,

First post here. Just wanted to say thank you to the community. I research a lot before a project, and everything that I’ve seen has shown the forums to be very friendly to newbs. Everyone starts somewhere.

Anyway… done with the mushy crap.

I’m about to start printing all my parts, but printed one first as a test. I’m in the US so I’m printing version C. I printed one of the lock corners and it has a bit of slop. The other posts that I found about things not fitting were regarding the hole for conduit/screws being too small. I can tighten the hardware down enough that the part will stop turning on the conduit, but it’s tightened all the way down. Is this indicative of a part that’s oversized, or does it look ok? I also don’t want to end up cracking parts later to get them to fit.

Dims and pics below. Let me know what you think. Am I overthinking this, or do I need to work on my printer calibration before proceeding?

 

Conduit Measurements

23.73mm, 23.51mm, 23.55mm (I rotated the conduit for each measurement. I guess it’s an oval)

 

Part Measurements

23.78mm, 23.84mm, 23.81mm

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2

Check your printer. Print flat square 50x50mm

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I ran into the same issue. My printer is hitting the designed dimensions pretty much exactly for the “J” parts. I think your printer is doing the same, when I dimension the “C” lock_corner part in Fusion it looks like it is a 23.8+mm hole.

I had to scale the lock_corners to 99% for a good fit. All the other parts were fine; you might find the same.

 

1 Like
4

For the entire history of the MPCNC and all it’s revisions the complaint has always been too tight, how the heck are there two too loose comments now…I have not changed anything. Hmmmm

5

Ryan - No doubt that I’m having an obscure issue that no one else does. Sounds about right for me.

 

I went ahead and printed an xyz test that I saw mentioned elsewhere on the forum. https://www.thingiverse.com/thing:2995270

Took three measurements along each axis.

x - 100.01, 100.00, 100.02 - Avg. 100.01

y - 99.78, 99.74, 99.72 - Avg. 99.75

z - 99.93, 99.94, 99.99 - - Avg. 99.95

 

Unless I should be chasing that .25mm on the y axis, I think I’ll move on to printing a different part to check like Edward suggested. Which part would be a good test?

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I am in the club as well! I just keep things like this on the radar and make notes for future revisions.

 

Good test, Z mounts.

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7

Printed the Z_Motor_C_Burly part. Very good press fit. Pops on easily enough, but as soon as hardware is tightened on there it’s not moving. I’m moving forward with the other parts now. :smiley: Thanks guys!

 

 

snapshot.jpg

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8

I beat the feet on mine with a hammer. Totally bizarre!

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I am having the same issue with my prints. The lock corner is screwed all the way tight but i can still spin the part on the conduit. Lock Corner ‘C’ seems a tad loose. I am thinking a layer of tape should snug things up?

10

Shawn you should do a large calibration part, 100mm. Verify your printer in all axis.

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Ok i have printed the calibration file that was linked earlier in this thread. Results are as follows:

 

X - 99.9 mm

Y - 100.4 mm

Z - 100 mm

They look pretty close to me. Should i be trying to calibrate?

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Nope, the only other option is the tubing. Is it round or oval, does it measure correctly?

13

Very slight ovality. At the thinnest it is 23.2. at the thickest it is 23.6. In the feet it fits very snug. It is just the lock corner that is slightly loose

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The feet are actually designed larger than the lock, that is a very odd situation.

15

Maybe check for slicer hole compensation settings or something. Too loose is an extremely uncommon issue as previously said.

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16

Thanks for all the help. Ill see if i can find an issue in my slicer

 

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Heck, a little silicone sealant just before pushing the tubes in and you’re good to go. :slight_smile: