PeterE builds a 3d Printer

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PeterE:
Me again,

Got a good day in the shop and made some more trial assemblies of the 3D printer.

First picture shows an overview of the mechanical assy as it ought to look when finalized.

Both the X and Z axis are more or less done, but as can be seen, there is a faulty component in the form of a broken X end idler (to the left). It turned out that my friend didn't find the correct settings so the part was un-necessarily brittle and broke as I aimed to push in the nut for the Z travel control. A quick look at the broken surface show34ed that there was no fusing between the layers so too cold during printing. Otherwise it looks as I expect.

A note of caution here for anyone trying to make a printer of the same style. As I started to put things together I was looking at the material list for info on smooth rods length. It said 350 and 370 mm, BUT, Do measure both the X and the Z distances before cutting! They turned out to be 430 and 470 mm respectively.

Next picture is a close-up of the mechanics.

A quick check showed that the setup is actually surprisingly stable. No back-lash or slop in either bearings or other things. I think this is going to work fine.

Then a closer look at the extruder.

The herringbone gears are also surprisingly slop-free! It feels like it is very well thought through so far.

One thing that I didn't like though is that I had to pack a larger amount of washers behind the screw head to locate the hobbed bolt for the filament feed correctly. There are obviously quite a few versions of feed stuff and I happened to pick the wrong one.

Well, I already found a solution :-) I will cut off the head, thread the end and use a nyloc nut together with Loctite to create a better positioned "screw head" using just one washer appropriately. That will be tomorrows job.

picclock:
Hi Peter

Great build thread, and pictures. Good to see how quickly you have got it all together. Thanks for sharing.

Re smooth rod lengths. The info I have is X=370, Y=350, and Z=320. Y bearings limit movement by -95mm so overall y is 225mm after allowing 15mm per rod each end. Length of y rod is set by bearing spacing and required movement. Bearing end to end on my stuff is 95mm. Not sure why x length is so large.. . Is it that yours are different due to the wooden frame construction ??

Many thanks and keep up the good work

Best Regards

picclock

PeterE:
Hi picclock,

Thanks, knowing the forums desire for well told projects I am trying my best to write down what I do and find.

The difference between the lengths of the rods is, as you say, due to to the different sized portal. Since the Z rods are positioned by the corners of the portal they will by default have another size. Same with the X rods that then must be cut to fit the Z rods positions.

This got me worries for a while and I wondered if I cut the portal to the wrong size from the beginning, but I didn't. The advantage of this is that I get a greater height for the extruder travel which in turn equal taller objects if I want to.

Next week is business travel week so no shop activities ...

/Peter

picclock:
Hi Peter

I have been very tempted to up the build platform/size on mine, but have resisted so far. I suspect that an object 8" on a side for me is massive - and if I needed larger two prints joined would do the job. I think if I ever needed larger the cube type that nmrl was talking about may be better as only the head moves, but I can't see myself needing something so large.

I've managed to cut the mirror bed glass for mine now after breaking loads of it :wack:, so I hope to be able to mount the bearings to it soon.

Bad luck about the travel - but if its like over here, eating out on the company is not too bad.

Best Regards

picclock

PeterE:
Just a quickie this evening,

The adjusted filament feed bolt now looks as below.

I cut off the hex head and threaded the end. Used an ordinary nut and screwed the whole thing together. After matching the feed knurling with the filament hole, I unwound the nut, put a drop of Loctite on and screwed it back together again. Now waitning for the Loctite to cure completely and then I will tidy the end up flush with the nut so it looks more or less like an ordinary bolt head. That will save me a bunch of space.

/Peter

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