After having a laser job fail because the vibrating plates actually moved the piece of plywood 3mm to the side by the end of the job I spent some time troubleshooting.
I found this fixed it:
Taping the pieces together isn’t it. The coaster under the corner is.
I realized the bottom of the carriage is flat on the cross bars and has room for rollers to ride on the top of the linear module rails. Providing a small lifting force underneath the carriage allows for 2 major improvements:
- Any vibration is damped to the linear module body
- Any downward pressure away from the center no longer deforms the build plate. Extremely useful for CNC, less so for 3DP, and not really for laser.
My initial thought on a permanent solution is to design a printed insert that serves as a roller bearing carrier and press fits around the support bars. The rollers will be allowed to leave off the ends of the linear modules and return - no issue since the downward force will always be under the toolhead, and that side of the build plate will always have a roller under it on the rail.
Something like this:
Thoughts? Obvious improvements that could be made to the design before I start building one?
@brent113 I’ll try that.
Balken.stl (37.0 KB)
I will use a 25x25x1mm aluminum square tube as the running rail. A threaded bolt goes into the two 4mm holes which I screw into the screw holes in the pressure frame and then use nuts and washers to adjust the distance between the aluminum rail and bed. In the 8mm hole is a smooth bolt that holds a ball bearing. Let’s see if I can use it to align the print bed a little better. Photos will follow as soon as the machine is free and I can start the conversion.
Because the bed wobbles so long, the long print went wrong, so plan B. Stütze.stl (19.4 KB)
Installation takes place. There were still a few changes.
If you have other aluminum profiles, you can adapt the part.
Bettstütze-3.FCStd.zip (99.5 KB)
Rename file, cut zip from filename.
and now action
That’s great! I like it. I could see how there could be some issues that creep in if the base or any of the pieces introduce any issues with non-parallelism with the modules.
Do the initial tests seem like it’s more flat?
The rocking of the plate when changing direction quickly has become less on one side. The two aluminum tubes are only fixed in the pushing direction, they can move sideways. The holder for the ball bearings and the support has lateral guides to the aluminum profile. That pushes the rails by itself where they belong.
Nice side effect, the four corners of the heating bed were always about 1.5-2mm too deep for me. Push the bolts up and the bed is almost straight.
Wow this is neat, you made a little slide carriage essentially yeah? That would force some uniformity to lessen wiggle room for vibration and i can also see how it could be useful in adjusting the leveling as well.
You guys are awesome!