Looking for comments about Deltas...

[Ian Smith]

I'm on my 3rd xyz printer and getting what I consider good quality and reliability. I've seen a couple of Deltas in person and just find they are so much more interesting to watch than the standard. I have some spare motors, Arduino/ramps1.4 and a small amount of open beam. Is it worth trying to make one from scratch, or should I just spend the money and get a kit? Which kit is better than others, or what resources have the best info for doing it from scratch?

Or are they fun to watch, but not worth the trouble and I should just stock with what I know. This would be an additional printer not a replacement.


Hoping for an interesting discussion.

[Nick Wimpney]

Well, the main advantages are they look cool, they can be very simple mechanically, all axis are identical (less parts to source), and they can be very fast (limited mainly by your hotend).

disadvantages is they're quite tall, which may or may mot matter, a bit less well-established in general, and there's a bit of weirdness caused by limiting factors due to using a slow 8 bit processor.  Generally your flat surfaces will be less smooth than a well tuned cartesian.

I built mine using smooth rods like the Rostock, but adapted to use spectra fising line instead of belts, and RC ball joints on CF rods, instead of goofy printed u joints on plastic rods.  It's pretty easy to build that way, but you do need to be quite precise when positioning the parts that hold the vertical rods, and setting the rods to exactly the same length.  My first attempt was a little sloppy, and while it printed well visually, I ran into problems printing towards the edges of the table, and all of my parts were very slightly distorted.  Gears I printed worked, but were slightly oval so the mesh was a bit tight in some postions and loose in others.

The second attempt fixed that, but the linear bearings I had were crappy and have since chewed up the rods, so I'm having to deal with that now.  I'm using some plastic bushings I made at the moment, but the friction is still a bit high.  I'm going to try some different lube, but might eventually rebuild with new rods and better quality bearings.

I haven't tried any of the designs that use the openbeam.

I would recommend sticking with a bowden setup if you're going to do a delta.  I'm not sure why the kossel went back to direct mounted.  One of the big advantages to a delta is the low moving mass, so mounting a stepper on the head seems to be a bit of a silly regression to me.  Of course, the tradeoff is that bowdens have more trouble with oozing, etc, and need a lot more retraction (which works poorly with some hot ends)

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[Ian Smith]

Thank you for the quick response.  OK I'll do some more reading and try one from scratch. If it doesn't work out, I may buy a kit.  Any other suggestions would be appreciated.

[John Biehler]

I'm a big fan of the Rostock Max...a few 3D604 members have them and I've been very impressed with their quality. For $999US for a complete kit, it's very reasonable considering the build area....you can also make a Kossel Mini for a little less. 

Gerald (a member) has also upgraded his electronics to a Smoothie board and it is the set up I'd go for if I was to buy a delta right now...I included the SeeMeCNC kit in my holiday printer gift guide as well.

That said, I'm still impressed with what Nick built and the fact that he strapped it to his bike and drove down to Maker Faire a few years ago and set it up and it worked better than some of the other printers. 

On Tue, Dec 9, 2014 at 9:28 PM, Ian Smith <iansm...@gmail.com> wrote:

Thank you for the quick response.  OK I'll do some more reading and try one from scratch. If it doesn't work out, I may buy a kit.  Any other suggestions would be appreciated.

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[Kimball Andersen]

I own a Solidoodle 2, and built a Rostock Max at work.  I will say that while the RMax is a nice kit, the beams and joints that it comes with are a bit sloppy, especially if you want to move towards a multi nozzle setup.  We ended up replacing the stock rods with the carbon fiber rod kit from trick laser, which improved it substantially.  If I were you I would build it from scratch, but go with magnetic ball ends and precision cut rods.  Calibrating the system is critical, and the less slop you have in everything, the better.  Once they are calibrated well though, they print beautifully.  it took me months of calibrating my cartesian to print perfectly round cylinders, while the delta does it effortlessly.  

K

[Nick Wimpney]

yeah, everyone I know with a rostock max has swapped off the plastic rods.

On Wed, Dec 10, 2014 at 2:55 PM, Kimball Andersen <pyrop...@gmail.com> wrote:

I own a Solidoodle 2, and built a Rostock Max at work.  I will say that while the RMax is a nice kit, the beams and joints that it comes with are a bit sloppy, especially if you want to move towards a multi nozzle setup.  We ended up replacing the stock rods with the carbon fiber rod kit from trick laser, which improved it substantially.  If I were you I would build it from scratch, but go with magnetic ball ends and precision cut rods.  Calibrating the system is critical, and the less slop you have in everything, the better.  Once they are calibrated well though, they print beautifully.  it took me months of calibrating my cartesian to print perfectly round cylinders, while the delta does it effortlessly.  

K

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[Ian Smith]

OK, thank you to everyone for the comments.  This will be a side project, so it won't be done this week... Any suggestions for places to read up on the correct ratio for dimensions and suggestions for software?   I'll start working out the basics, and start putting something together.

[Nick Wimpney]

I just used the dimensions of the rostock for reference.   I think the info is on reprap.org  they actually aren't critical,  but maintaining similar rod angles is probably a safe bet. I scaled mine up a bit so I can use a 12" tile for a print surface.,  just do it proportionally and it will be fine.   I added 20% to the centre to tower,  so also added 20% to the diagonal rod lengths.  They are all adjustable in the firmware.   As far as height goes, it doesn't matter. For a rough estimate,  just take the build height you want,  add your diagonal rod length,  hot end protrusion and the height of the motor mounts. You will be able to print a bit taller near the middle of the table.   I wouldn't go too crazy though,  unless you plan to print a lot of vases. I used 762mm smooth rods on mine,  and that gives me about 30cm of max height. The more height you have,  the more you have to worry about wobbles.

[Gerald Orban]

I've been extremely pleased with my Rostock MAX and have had it almost a full year now! My previous printer was a Makerbot Replicator and the quality difference even with stock parts is quite distinct. I can't comment on the stock arms for the MAX as I built the kit using the carbon fiber arms from Trick Laser.

The quantum leap in print quality as John mentioned came from my upgrade to a smoothieboard which is a 32-bit microprocessor for 3D printers using a general purpose firmware written from the ground up to produce very high quality machine motion. If you buy a MAX, I'd suggest you go straight to a smoothieboard as well :) It's not that difficult to setup!

The only caveat with delta printers are that you have to be absolutely positive that your towers are perpendicular to the plane of motion of the hot end otherwise you'll get significant bowing when the print head reaches the extents of the build surface. So make sure you have a good quality carpenter's square during assembly and you'll be set!

[Ian Smith]

Sounds great! I'll think about it and then talk myself out of one that could print a lifesize version of my mini-me.ca scan. 8)

I dont think i will try anything crazy, just want a delta to play with.

On Dec 11, 2014 1:37 AM, "Nick Wimpney" <nick.w...@gmail.com> wrote:

I just used the dimensions of the rostock for reference.   I think the info is on reprap.org  they actually aren't critical,  but maintaining similar rod angles is probably a safe bet. I scaled mine up a bit so I can use a 12" tile for a print surface.,  just do it proportionally and it will be fine.   I added 20% to the centre to tower,  so also added 20% to the diagonal rod lengths.  They are all adjustable in the firmware.   As far as height goes, it doesn't matter. For a rough estimate,  just take the build height you want,  add your diagonal rod length,  hot end protrusion and the height of the motor mounts. You will be able to print a bit taller near the middle of the table.   I wouldn't go too crazy though,  unless you plan to print a lot of vases. I used 762mm smooth rods on mine,  and that gives me about 30cm of max height. The more height you have,  the more you have to worry about wobbles.

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[Kimball Andersen]

Could try something like RichRaps 3DR: http://richrap.blogspot.ca/2013/07/3dr-reprap-delta-printer-part-1-release.html

K

[Graeme Bennett]

I have four Delta printers to sell, if anyone is interested. 
The biggest and best of the bunch is the Canadian-made Boots Industries BI v2.5, as detailed at bootsindustries.com. I'm selling it (fully assembled) below my cost. Contact me or text me at 604-442-3512 if you are interested. Here is a sample of its impressive print quality.

I also have a Canadian made Mixshop Kossel printer (as seen at mixshop.ca), also fully assembled, will sell below my cost. Contact me for details.

[Ian Smith]

Just to update everyone on my progress. When I saw Graeme's post, I decided to jumpstart my build by picking up a used printer.  From what Graeme says, this one is pretty new.  

It's from Mixshop.com  http://mixshop.com/index.php?main_page=product_info&cPath=59&products_id=220&zenid=4ue1oku2i20k0gpc744po3i537

After spending the evening looking at it. Almost all of the plastic will need replacement or redesign.  From the extruder to the corners, it's all just a very weak design. 

But it will do what I wanted by giving me a good idea of the proportions for the printer, and supply the extra parts that I needed to get started. 

[KP Chiang]

Nick,

I am seeing the same issue you described : round disks came out very slightly oval.   As result, things that are supposed to mesh perfectly just don't.   Do you remember what you did to fix this?

Back when my delta printer was cable driven it was worse : a round cylinder would have three small flat sides corresponding to each pillar.

Thanks

[Kimball Andersen]

Does your end-effector (the plate that the hotend is on) rotate at all? (it should stay perfectly parallel to the build plate, at all times)

[Nick Wimpney]

I think I probably had either uneven placement of the towers, or uneven diagonal arm lengths.  Either way, when I built the next 2 revisions, they didn't have that problem.

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[KP Chiang]

thanks for the replies.

Kimball,

I have never measured parallelism of the end effector but I do know the nozzle touches and zeroes on print bed everywhere.   If I grab and shake the nozzle(when cold) I can feel some springy movement but definitely no free play.

Nick,

I see.   My delta (Boots Industry V2.5) came with pre-drilled metal corners and beams so I am assuming the alignment of structure is ok.   But the rod length on mine is wonky as I have found a few rods that are not glued properly.

[Derek P]

I have built a couple of deltas from scratch and though I enjoyed both builds they were not weekend projects. They both need a fair amount of maintenance and upkeep. They do not travel well. The best source for current information is this google group:

https://groups.google.com/forum/#!forum/deltabot

David Crocker is well worth following and he is an evangelist for 32bit controllers and specifically the duet. 

[Jeremiah Timmins]

I bought a Rostock max 2 delta in November `15 and built it in a week.  I was too excited and impatient to properly calibrate it but have been using it despite the half build volume (6" vs 11").  It hasn't been an issue yet as all of prints fall within that area.
I have nothing to compare it to but deriving a conclusion about prefab vs reprap evos isn't hard.  I believe the maker bots and other prefab units have limited issues.  I've diagnosed a number of minor issues (pla composites affecting consistent output, getting clogged or not flowing at a consistent rate, hot end temperatures falling under target, print adhesion for place and abs, overheating wires, etc).
It takes an obscene amount of time to design something that works well, especially from the first print.  Combine that with a delta or any reprap and you're working long hours.  At least initially.  I have noticed that factor leveling off if its put to a graph, time vs productivity. 

This isn't a hobby for wimps.  It takes brains, time, creative juice, experience and some bandages to gain the wisdom to create anything worth bragging about.  It can also help to have someone validate all the stupid things that you make...that's one of the many reasons I love my family.

Best of luck with your adventure!

[Ian Smith]

Thank you to everyone for your replies.

Just to update everyone on my delta work. I picked up a boot industries V2.5, and a small delta on craigslist. The Boots was working reasonably well, but results were inconsistent. Eventually, I realized one end stop has not working properly. I'm going to debug, probably a broken wiring connection. The small delta parts were made with very brittle PLA. I'm slowly making new parts for the small delta with a better PLA and different design. It's not a priority, but it is slowly taking shape.

The deltas are still much more interesting to watch than an xyz. Currently I'm getting better results with the Rigidbot.

Ian