@dc42 Ah, thanks for the name. I'm able to find some. I also considered a vacuum to hold the bed in place and electro magnet but they seem impractical.
Also, is there any build surface, beside glass, that can be used for high temp plastics? As glass is heavy and also cannot be used with magnet base.
I am working on a larger printer with heated chamber and I am looking for a high temperature (200°) bed that has a 700x700mm print area.
The heater is not really a problem as I can use a silicon heater with no adhesive and sandwich it between two aluminum plates. I also though of splitting my bed in 4 heating zone with 4 smaller plate, to help with leveling and thermal expansion. But I am very open to suggestion on this too.
My main problem is build surface. At this size, it becomes harder to manipulate. Also magnet based surface, which I love for smaller printers, cannot be used at this temperature as magnets are usually rated for 150°. I was thinking of creating some kind of drawer that can be pulled out of the printer (my gantry moves on three axis).
@Phaedrux Thanks for the reference. For some reason when searching with google their products do not come out.
@deckingman Yeah you are right. I'm sorry, I'm a bit under stress and I should have taken more time to pose the actual problem. I sometime forget other people aren't in my head and that it is important to share information. I really appreciate your feedback and I am sorry if I made you lose time.
Yeah, reducing the motor is a good option to increase accuracy of higher pitch belt. I found different 8mm pitch high temperature belts that, I guess, are designed for automotive. I will need larger pulley are they are less supple than smaller pitch, but with reduction on the motor it should be ok.
@deckingman the head is large because the gantry is 1200mm and there is a pellet extruder and a laser on the head. We are working on a technique that improve strenght and smooth the surface with a laser after extrusion. The weight is the head + gantry + water cooling + motors to manipulate the extruders and laser (small "mini axis"). The extruder alone is already 7kg. We have a working prototype of a smaller machine on which we use regular belts with a normal fdm extruder and much lighter gantry. We use high accel for laser moves.
As a side note, GT2 12mm wide seems to require custom made pulley. I cannot find off the shelf clamping pulley larger than 9mm wide for 2mm pitch. I use mostly McMaster and misumi. I found some chinese pulleys on ebay and alibaba but they are all set screw.
@mendenmh Yeah that's one possibility, but that's more hassle for tensioning and such.
@deckingman I used 1g as max accel as it gives plenty of margin over the accel I am going to use. At 1g, it's 250N, with a 20mm diameter pulley, it's 2.5N/m torque and 1500RPM for 500mm/s max speed, which is about 400W (for some reason, most belt sizing guide I found from manufacturer uses watt or HP), and for this gates recommend 25mm wide belts. I also did the math in the gates belt sizing guide.
@deckingman I actually have a design with rack gears, but it requires moving motors and some axis requires multiple motors that have to be synced. Belts let me have one motor per X and Y axis. For such a large machine I though having direct mechanical coupling was better because if motors unsync for any reason it could cause major damage.
@deckingman my moving mass is 25kg and I'll aim for highest possible accel. I use nema 34 clearpath servo.
@elmoret Yes I found those. But I forgot to mention that I need wider belts than 12mm because it is a very large printer, those have a power rating too low for my needs.
I am building a new printer that will be heated, and some belts will be subject to 120°C air.
Do you know any belt that can work at this temperature? I found the GT4 from gates which goes up to 130°, but it's only 8mm pitch.
Any profile that work for positioning will work, I'll just get the pulley with the belts.
@Proschi78 As I said, if I select the tool before doing G29 so, T1 + G29 it works. But I think it should work without T1 as I specified U axis in M557. Also it should not go crash in other tool. Perhaps @dc42 can chime in. I'd be happy to try to help debug the issue.
@Proschi78 No. mesh.g doesn't exist.
@Proschi78 No, G29 doesn't affect selected tool.
@Proschi78 No, because if I select T1 before doing G29 it works.
@Proschi78 Yeah, but the point is that it shouldn't matter.
I hope all axis, at this point no tool is selected.
I expect G29 to be able to probe using the U axis.
Only the first point work, then the head goes crashing on X carriage.
@Proschi78 My tool macro are all empty.
If I do T1 before probing it works, but it got me confused because I thought M557 with U parameter would use correct head.
I still think the head crashing is a bug.
@chrishamm After many prints, this issue did not appear again. So I have good hope it is fixed.