Oh what fun I’m having with spectra line!
Spolier - I’m not :(.
Made a stupid design error with the bobbins I’m using to secure the spectra to the outer shafts of the gantry, so on 2 corners, the spectra (once tightened) cuts through the plastic… DOH!
Anyway, more bobbins being printed right now so maybe maybe I’ll have both axis moving tonight. On the up side, before the plastic gave way, the x axis was moving nice and smoothly and I even wired a stepper up and got it moving via gcode. REALLY want to put the Z axis together but there’s no point until I’ve sorted the x/y gantry out.
Just a quick question, I’ve noticed a lot or some people using spectra line as belts and what not including the 3dr I’m building. How are the steps per mm calculated is it just guess and measure?
I’m curious if a prusa I2 would benefit from spectra line?
@Jeremy_G_WeisTek_Eng calculated from the diameter of the pulley just like regular belts.
Duh, thanks
@Jeremy_G_WeisTek_Eng Spectra has to be TIGHT to ensure you don’t get any backlash, so on a Prusa or any of the Mendel style bots, you’d need to make sure your x ends are clamped very tightly onto the x rods otherwise you’ll not be able to get the spectra tight enough before things start slipping. On the up side, it should remove any artifacts arising from belt teeth and lower the aggregate inertia/momentum of the x carriage. By the looks of them, the pulleys @Richard_Horne designed for the 3dr should be easily adapted for use on a Prusa.
The prusa has a habit of flexing the frame if the belts are too tight. I learned this a long time ago. I follow the @Triffid_Hunter method of tightening my belts. If I can’t play Smells Like Teen Spirit on the belts, they aren’t tight enough.
I prefer the baseline from A Forest by The Cure but other than that my belts are equally musical.
@Tim_Rastall Awesome pictures. After doing more research, in thinking I might stick with belts for my upgrade design. I’ve been following Polygonalhell’s blog for a core xy using spectra, and it seams that the spectra is making the design much more complicated. I’m going to spend the money for gt2 parts to minimize development time. I had hoped to use spectra for the reasons you listed, but don’t want to deal with the added issues of spooling and slipping.
What design error did you make and how did you fix it?
@John_Ridley do have a link? Also, are you buying drive pulleys or printing. I’m planning on just using bare 608 bearings as idlers
@Eric_Moy $5 a metre is piracy:
@Tim_Rastall dang, bookmarked.
@Shauki Actually a very simple design. The unique part count is very low and the drive mechanism is elegant (Stolen from Ultimaker). I’m also only using 1 stepper per axis, unlike a lot of bots that use 2 for Z.