Darkly Labs Community

Upgrading E1 Rail System w/o 3D Printing

I’ve read of people upgrading their rail system - notably adding a second rod to each Y rail, to prevent the carriage from twisting.

I’ve also tried to make upgrades to my emblaser by adding air assist using 3D printing, and found my cheap 3D printer to be unsatisfactory for the task.  I’ve also noticed the ‘straps’ that hold the bearings in place have broken, and every now and then a job has to be aborted because of a problem with the carriages.

So I’m thinking of replacing the carriages (initially the left and right carriages, stretch goal - the laser carriage) with laser-cut MDF box carriages, and at the same time adding an additional rod to the Y rail.

I’ve got a suite of Python (2.7, ugh, I know) code for Inkscape that helps me design sturdy, tight-fitting box-like structures out of laser cut material.  And I’ve just started adding a section to deal with making the upgraded carriages.

 

I’m going to base my design on the 3d printed ones here:
https://darklylabs.zendesk.com/hc/en-us/community/posts/208184318-E1-Upgraded-Rails

Although mine will have none of the graceful curves of this print, it will instead all be 90 degree joins and box-like parts.

Some things that I’m not sure about, having not worked with bearings before:

  • there are 3 ‘sections’ to the bearings.  I noticed that the voids in the 3d print tend to “grip” the centre section and leave the outer rings not touching anything.  Is this necessary?

  • the lower rod from the X axis passes into the Y carriage and rests against the bearing.  Is this just a simple way of making sure that it lines up correctly?

  • the post above links to an ebay store where the bearings can be bought.  Does anyone know where I can get the extra rods, and their dimensions?

 

Finally, I’m getting a lot of the dimensions for the parts - the distance between X rods, distance into the carriage, rod diameter, etc, from using a measure tool on these STLs.  I can get my calipers out when I get home and confirm some of them by hand, as well.  But are they listed anywhere?

Cheers,

Antony

It’s been a long time between drinks.  I haven’t been able to use my cutter for a while, been super busy and can’t seem to get into the workshop to do some cutting.

I have, however, been working on my design during my lunch at work, and I’ve had the parts cut by a local company to test it out.

So I’ve finally assembled the left and right carriages, laser cut out of 3mm MDF.

Now I have to see when I can get time to see if they fit in the machine, and all the belts and pulleys line up like they should.

I’ll post the final svg when I’ve confirmed it’s working.

Cheers,

Antony

Keen to see how this works out. Keep us updated!

A disaster with my last cut. I hadn’t inserted the pins for the pulleys before I assembled and glued the carriages.

The hexagonal cutout in the layer above where the nut sit was not strong enough to hold the nut in place as I tightened it (after using tweezers to navigate it into position).  1 pin in each carriage took so long to try to tighten that it ruined the fit for the pin, so it would no longer sit straight.  Getting it out ruined the rest of the carriage. :frowning:

Undeterred, I ordered another pair to be cut for me locally and just assembled them:

^ During assembly.

 

After I slid the outer covers on, I suddenly couldn’t close the left carriage, and to my horror, noticed I’d put the bearing cradles in the wrong order!  At that point the glue was already holding!  The only difference between #0 and #1 is the depth of the cradle’s inner block.  With a quick snip of my wire cutters, I removed the offending piece of wood:

 

And now, wrapped in elastic and glue drying next to their original counterparts, both carriages.  (Outer covers are not glued, don’t worry, I can still insert the bearings!)

 

Plywood may be a better option?

It would give you more strength.

This is true - if there are problems I may need to get it cut again in a stronger material.

It’s something I didn’t really think of as so far MDF has been strong enough for all my previous applications, but it’s the “local strength” that’s the problem here, if that makes sense.  The tightness of a screw/nut is greater locally than the strength of the mdf, causing the nut to keep spinning and gouging out a circle instead of stopping hard against the wood. 

I may consider whether I can get a tiny araldite spatula back to where the nuts are, and have them locked in resin before I put the new carriages into action.  That might mitigate the need for making it in plywood.

If I do have to make them again, I hope I can get exactly 3mm-thick plywood - although my code should deal with changes to the thickness of the material, there might be parts that don’t fit together if the material needs to be thicker.

Every time I get back to this, I run into another problem.  The carriages that I assembled above (2 months ago!) didn’t fit in the machine; they’re bulkier than the original 3D printed parts, and so were clipping against the acrylic edge of the emblaser.

I’ve made modified brackets to hold the rods, that hold the rods 10mm above the acrylic, and just inserted the right carriage.  I then proceeded to start installing the brackets for the left rods, and found that the rods that I had ordered from Darkly Labs months ago are not the same size as the ones I already had.  They’re 410mm long, instead of 400mm long like my originals.  They don’t fit!

I’m looking now at whether I can trim them down with a hacksaw (my brother has a workshop with a vice and an old hacksaw), or possibly his grinder (don’t know the actual name of it, it’s 2 spinning ‘wheels’ of stone that he uses to sharpen his chisels). 

Or I could cut a couple of holes out the back of one of the brackets I just made and then apply some epoxy glue to hold it in place with it sticking out a little.

 

Something else I’ve been looking at is my air assist module, and I’ve drawn up a design to replace the wooden “chamber” with a brass nozzle at the base, and instead am trying to connect my airbrush to a football needle, which I have a bracket designed to hold it pointing directly where the laser would be cutting.  I’ll update that thread of mine when I’ve got progress.  Currently in hose-fitting-hell, finding it nearly impossible to get information about what actual sizes various airbrush/compressor/bike pump fittings actually are.

Anthony,

I found this the other day that may help you with your hose connector problem. You do need a 3d printer though.

https://www.thingiverse.com/thing:3764039

This has been put on hold for a while.  Every step of the way I’ve run into a problem of some kind, and because of the state I’d left my Emblaser in, I couldn’t do any other work until this was finished.

For the last problem I had above, I went with the “drill a hole out the back of the brackets and just fit the rail in”.  But I realised as I was assembling the Emblaser and about to tension the belts, that since I’d raised the rails up ~10mm, the motors were in a different plane to the pulleys.  The belts were clipping against the main chassis.

In order to get my machine back to a working state, I ordered a set of the v1.5 gantry upgrades, and so on Saturday night, I got my laser fired up and ran the calibration test.  It all looks good, moves smoothly again.

Have solved the air-hose problem.  I’ve got an adaptor that connects the air brush hose to a bike pump hose, which connects to the football needle.