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Homebrew engraver to 3D printer Mod
Joules:
Bill if you just go with PLA you can pick which drive you want. Bowden is good for speed as your head is lighter and can have better rapids. If your wanting to print with any springy filament you want direct drive as ooze and metering are a nighmare with Bowden.
BillTodd:
Thanks Joules,
What sort of speed and force are required for the feed motor?
The ebay hot ends seem to use a 12v 40w heater and what they call a thermistor. Is the thermistor a pt100 typically or is it really a thermocouple?
picclock:
Hi bill
Thermistor is usually a glass bead encapsulation resistive element, typically 100k at room temperature, which reduces in value as temp increases. Upper temp limit is normally 300C. Can get head heaters for 24V.
Feed force depends on head temperature/nozzle size/extruded material type. Std 1.75mm filament feeders use 3.5:1 geared reduction driving a toothed 8mm bolt which is about another 8:1. so overall drive ratio is 26:1, driven with a 3-4Kg holding torque stepper.
Best Regards
picclock
BillTodd:
So just a generic NTC thermistor . How is it calibrated ? I've seen pictures of the control panel showing temp in degrees F & C .
Hmmm, the force is strong in this one - looks like I'll have to get hold of some filament and experiment .
Today I mostly made the Z axis slide - turned out OK smooth motion without any play . I have yet to drill the mounting holes and I stil have a motor plate and nut part to make .
BillTodd:
Found time to make a motor bracket and mount the Z axis . It moves nicely, albeit at a slow 6mm/s .
The axiz is still too long ATM but I want to have enough spare movement to raise the X axis to a more useful height should the printer function well ( I would just have to make a pair of new vertical arms)
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