My simple delta carrier

Hi guys,
I don´t have experience with deltas but I´d like to build one.
But the prices for v-slot extrusion and the related roller bearings are a bit high for my liking.

So, I designed a simple carrier which would run on smooth 20x20 aluminum extrusions instead of v-slot.
And it uses two standard 623zz bearings and two hobbed idler bearings from the MK7 Makerbot extruder.

I´d like to hear your experts opinions before I embarrass myself, publishing it on thingiverse

Thanks
-Olaf

I like it. Especially I like how you use the two bolts to tension the part together. You could even use longer screws and put two small springs on the other side to apply consistent force. That would absorb variations etc.



I have also played some with alternative ways of mounting on the extrusions. My experience is that I look too much at the minature bearing and use that as reference for size. You might have a bit the same. Remember your bearing is just 4mm wide so while the part looks proper dimensioned compared to the bearing you should consider if you will be able to print and get strength at those thicknesses - Or if it will crack the moment you start to tighten up.

Try to print it - After all, it is the big advantage of having your own rapid prototyping machine that you can... Well... Prototype rapid

I printed it and it twists a lot ( like Willenbrook said in his thread )

I redesigned it and printed again, now using 6 flanged bearings.
The plate is split now and you could use bigger bearings as well.
I made the whole SCAD design parametric. Changing the bearing dimensions would resize everything ( untested yet )



The idea with the tension springs was in the back of my mind too. But I was to lazy to draw it in...

It will be noisier than the roller / V-slot design. We will see if the price difference is still attractive enough to build it.

I can get 6m of the flat 20x20 extrusion for ~20€. What about openbeam $$$?
Has anyone build his delta with standard t-slot extrusion for the short horizontal struts and use openbeam only for the long vertical struts?
-Olaf

Edited 1 time(s). Last edit at 08/03/2015 02:54AM by o_lampe.

Good morning,

Actually I think I liked the first iteration better. With this new one you don't have the best load paths. In particular I would go back to just one direction of tension and I liked the grooved bearings pushing sideways. I think the twisting can be fixed by two things:

1) Doubling the material thickness and making supporting ribs

2) The groved bearings pushing on the backside - Why don't you use the same concept on the front???

Like:


o
|
-----o
|
o


Where each "o" is two groved bearings pusing against the extrussion. That would give you a total 6 points of contacts which should be enough for stability and twisting.

Quote
o_lampe
[SNIP]
I can get 6m of the flat 20x20 extrusion for ~20€. What about openbeam $$$?
Has anyone build his delta with standard t-slot extrusion for the short horizontal struts and use openbeam only for the long vertical struts?
-Olaf

Here in Brazil I pay R$14,75/ m ( 4€ per meter for 2020). Delivered within a few days. You should be able to find the same in Europe.

Just made a video of the carrier running slow back and forth.
It was totally free of play but still running smooth and silent. Only at the turningpoints I heard a sharp noise. The Ramps testcode makes the stepper yerk.

I´ll change the design a little to make assembly easier.
-Olaf