Minimize rocking

I’ve noticed that when I have prints that go close to the front edge, and especially with fill operations that have front to back movements, the edge of the plate can rock at least a millimetre vertically, possibly more. As a result, I see less precision on the print in that area and more issues with the first layer adhering mostly near the corners.

I’m on an A350 which probably exaggerates the issue with the larger sized plate.

Anyone have any tips or DIY tweaks to make the plate a little more stable in these operations?

i have a same… but more annoying on the cnc mode… i’m thinking to build or print a rail system under the carriage… both side of the table… hope fully this way the table get more stable :thinking::man_shrugging:

I had the same issue so installed some linear rails. I didn’t want to start drilling holes in the snapmaker base so made some new lower feet so the base was the same height as the enclosure bottom rail and used that to clamp to. Not the most elegant solution but it works.

5 Likes

I’d say that qualifies as elegant. Any plans or a parts list that you could share?

That it does, much better than any others I’ve seen.

@MonkeyHarris are those hgr 20?

Thanks for the kind comments. The extrusion is 2020 x 800mm long and the rails are HGR15 x 800mm long. I’ll dig out the sketches of the feet and clamp blocks this weekend and post them.

2 Likes

That’s great!
The A350 has more space and you can place the slide rail, but has anyone tried hard with the A250?

I’m an A250 and I’ve considered many things but haven’t been able to make it happen.

Just measure total length of the enclosure (without counting vent) and get the same rail but shorter length, everything else will be the same

Unfortunately, the A250 has almost no gap between the Y and Z axes, so a slide rail cannot be installed.

We are looking for a better way, but have not found it so far.

Oh gotcha, I didn’t realize

@Blockmodule what is the gap distance on the a250. I have an idea but need to know the distance and I do t have one to check it myself

I’m on the road so I’m not sure exactly, but I think the distance between the Y-axis linear rail case and the Z-axis linear case was less than 20mm.

The only thing I could have done would have been to place the MGR9mm slide rail vertically.

Either way, I gave up because I could not fix the slide rail due to lack of space.

1 Like

That might be enough space for what I have in mind, I’ll write up the plan once I get the hurdles taken care of and design a bearing guide. Growing up my dad had a TON of loose ball bearings and so I tinkered with them a lot and got good at creating little bearing guides and sleeves for various reasons that served absolutely no purpose other than keeping myself entertained.

I have been thinking about a similar upgrade for my A350 and I was wondering about putting just ONE rail with two carriages (one for the front edge of the bed and one for the back edge) in the center of the bed. This would give triangulated support for the bed and since the purpose is only to give support for rocking, maybe this would be sufficient? Presumably one rail could be mounted in the center for the A250 too. What do y’all think?

– James

Of course you would need to relocate the cable splitters that are installed in that space by default…

i love this… good job… that’s exactly what i had in my mind

People have done it but the purpose of the rails on the side isn’t just for the rocking, it’s to prevent the corners of the bed from dipping low and keeping it more level with the rest of the bed.

So… we need to think outside the box for the a250.

I’ve been thinking, what about using a t-track.
Ignore the length of the rail, the purpose of these photos are to determine fit between the z and y axis



Could design a bracket for the frame corners that has arms and holes to slide a Delrin wheel bearing that is very commonly used on belt printers, it wouldn’t need a wheel on the other side because the frame itself would ensure the wheel stays in the track.

Someone also made an alternative to delrin wheels on the reprap forums. I wonder if it could be adapted to join to a bracket for the frame. The piece in question is the green part which is not printable but actually a specialized part made by McMaster Carr to be used as a t slot bearing, multiple sizes.

image
image
image

I also came across this, the bearing has a total width of 19mm, on a 20mm t-slot rail, with an adapter in the t-slot to mount the upper guide rail. But it won’t work if the space is less than 20mm as you said.

image

Here is the list of parts I used to build the support rails along with approximate prices (UK)

2 off 2020 Aluminium Extrusion 800mm long £18.50 off EBay
2 off HGR15 Linear Rails 800mm long
complete with 4 blocks £60 off EBay

4 off Replacement Feet for bottom of Snapmaker. I manufactured these myself (stl file included below)
4 off Packing Blocks to connect rail blocks to Snapmaker Cage. Also manufactured by myself (stl file below)
8 off 2020 Corner Brackets. £9.00 off Amazon for pack of 30

Fixings:

M4 Socket Cap Screws to bolt rails to 2020
M4 2020 T-Slot Hammer Head Nuts for above

16off M5 Socket Button Head Screws for Corner Brackets
16off M5 2020 T-Slot Hammer Head Nuts

The Feet are to replace the standard ones and lower the level of the Snapmaker base to the same height as the Enclosure Bottom rail. The diameter also fits the clamps supplied with the enclosure to prevent movement of the base.

The Riser Blocks sit on top of the Linear Blocks and raise the height so the snapmaker carriage sits on top.

I machined both of these parts out of Aluminium and Steel but I dont see why they cant be 3D Printed.

This is still a work in progress so is not yet perfect but help me immensely with a project i`m working on…

an M&M sorter. It`s based on a design by this guy…

I`m not affiliated with him at all but he has some very cool 3d projects.

Stl files:

Foot.STL (26.6 KB)
Riser Block.STL (75.3 KB)

4 Likes