Scara opinions

Falkia · 4 Sept 2018, 21:30

I'm just curious about the Scara printer type. For the deltas there are tons of information on the web about design guides and online calculators etc but for the scaras there is almost nothing to find.
If you compare speed and accuracy etc between those, what do you think?

My plan is still to build a delta printer but want to know a little bit more about scaras.

Thanks
Fr3Drik

fcwilt · 4 Sept 2018, 22:23

@falkia said in Scara opinions:

My plan is still to build a delta printer but want to know a little bit more about scaras.

Thanks
Fr3Drik
Hi,

I built three deltas because they are clever and are supposed to be fast.

Problem is I never have been able to get them calibrated so the bed is "flat" as it should be.

I have spent hours and hours working on them trying to locate the problems and fix them.

No luck.

My most recent printer is a Folger Tech FT-5 - my first non-delta printer.

I had that printer calibrated spot on in a few hours and the bed is as "flat" as I could hope for.

It simple prints everything I have tried on it without issue.

The only downside is that it is likely not as fast as a delta could be and it is pretty big - which is fine is you want a big build area (300x300x400 mm) but a bit of a pain to move around.

Good luck.

Frederick

deckingman · 5 Sept 2018, 07:30

@falkia The only one I've seen working is one that DC42 used as a demo machine and to test Duet electronics and firmware. I don't think he was a huge fan but hopefully he might step in here and tell you his thoughts (I know he is busy getting the firmware ready for the TCT show right now).

dc42 · 9 May 2018, 17:11

I currently have 3 printers:

My first was a RepRapPro Ormerod kit. It works but it isn't fast and isn't mechanically stable.
My second is the large delta. This is the printer I use for printing everyday stuff. It's fast, but I get occasional hot end jams (I think this is common with all-metal hot ends, because they are very sensitive to over-retraction, and a machine with a long Bowden tube needs a lot of retraction).
My third is a cheap Robotdigg SCARA printer upgraded with a Duet and some mechanical parts too. It's slow, the print quality isn't great, and it needs a huge amount of bed compensation because the arm sags a lot as the hot end moves away from the proximal axis. But it's very reliable. I think this is due to the combination of using a super-sticky filament (RigidInk PLA+) printing on cold blue tape, and a PTFE-lined hot end that never jams. I only use it for test and demo prints, not for anything serious.

I am a fan of deltas (now that I have found out how to build a good one), but for prints larger than about 450mm diameter or for multiple extrusion, I'd try CoreXY.

HTH David

Falkia · 5 Sept 2018, 18:28

@dc42 my plan is still to build a large delta (they look so cool in action ). Another type of printer that also looks cool is the Morgan type (some call them parallel scara) but I don't think the duet have support for it.

JoergS5 · 5 Sept 2018, 18:40

@falkia Had a discussion with David how to implement parallel Scara into Duet:
https://forum.duet3d.com/topic/5651/parallel-scara
I will need another few months to implement a prototype.

T3P3Tony · 8 Sept 2018, 11:39

@Falkia there are a couple of reasons I can see to use scara, both relatively niche for 3d printing. Voth are related to the fact they have a small base and print outside of that base area. A scara can be easily transported, clamped to a surface and then print on that. Also they can, in theroy print over a very large area compared to the size of the printer.

In normal 3d printing applications though the lack of rigidity (meaning sag and artefacts in the printing) make them a poor choice.