some improvement ideas

[dethegeek]

Hi

User of a 2nd batch of the Foldarap, I'm currently upgrading some parts to tne master branch (version 4)

I notice 3 things which may need improvement

rack lock design improvement

• the rack locks don't adhere strong enough on the aluminium profiles and may suddenly escape if the rack pushes them. I found that adding a 2nd leg on the locks makes the mount safer. As a counterpart, the bolt cannot rotate anymore because if I keep the length of the lock as is (required for the mount on X axis

original lock

my current design

This need to be validated with a mount attempt of Z sliders (currently printing)

rack pressure on motor's gear

The racks have a spring to push the gears in the gear mounted on the motor.

After a testing mount I believe that there is too much pressure on the gear iincreases a lot the risik of missed steps.

I think I'l upgrade the locks to push the rack on the aluminium profile. If I manually push the rack in the profile, and hang it vertically, less frictions allows the motor to fall along the profile. It seems there is no backlash thamks to the design of the teets. Also this eliminates the resistance points introduced by the imperfections of the prints (i used a 0.2 nozzle with PLA).

I will test soon how this assembly behaves when I give mower to the motor.

assembly of X axis aluminium profile on Z carriages

I always found that the X axis has a weak mount Z carriages.

I believe that the Z carriages in the 4.0 design may be improved to use a long M5 screw engaged in the center of the aluminium profile. Here is a draft to illustrate the the assembly of the screw and the profile.

There is enough room in the Z carriages to create a hole to put the screw's head in the carriage and not interfere with the Z axis profile.

I'm not sure yet if I can experiment this soon: I need to finish my current upgrade iteration, try a piezo Z probe with it and upgrade to Marlin 2.0

Note : If you're interested, I'm using Marlin 1.1.9 on a Minitronics 1.0 and may be a good improvement for all foldaraps versions.

[EmmanuelG]

Interesting ideas, especially the X axis assembly with the Z carriages :)

[dvanderfaeillie]

@dethegeek

Could you share this updated rack lock design?