T3P3 Kossel Mini Kit Release 3

Assembly Instructions

Chapter 2 - Base Assembly

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201 Motor assembly - Parts required

Motor brackets x 3

Motors x 3

GT2 pulleys x 3 (grubscrews pre-fitted)

M3 x 8 socket capscrews x 12

M3 flat washers x 12

NOTE: Kits may be supplied with OSM motors (all-black, as shown in the picture above) or Wantai motors (silver-and-black, shown right). The only difference is that the Wantai motors have shorter shafts so the pulley positioning varies as described below.

wantai11.JPG

202A Fit pulley to motor - OSM Motors

Note: The pulleys come with one or 2 grubscrews pre-fitted inside the hole. The motor shaft has a flat side - align the flat side with a grub screw. This firmly couples the pulley to the motor shaft.

The pulley is fitted with the collar and grubscrew at the outer end of the motor shaft, with 2.5mm of the shaft protruding. This provides correct alignment with the idler at the top of each tower. You can use the 2.5mm hex key supplied as a spacer to set the amount of shaft to leave protruding.

Tighten the grubscrew(s) firmly (but do not overtighten) with the 2mm hex key.

Repeat for the other 2 motors

202B Fit pulley to motor - Wantai  Motors

Note: The pulleys come with one or 2 grubscrews pre-fitted inside the hole. The motor shaft has a flat side - align the flat side with a grub screw. This firmly couples the pulley to the motor shaft.

The pulley is fitted with the collar and grubscrew at the outer end of the motor shaft, with the shaft recessed into the collar of the pulley by 1.5 to 2 mm. This provides correct alignment with the idler at the top of each tower.

Tighten the grubscrew(s) firmly (but do not overtighten) with the 2mm hex key.

Repeat for the other 2 motors

Wantai-pulley2.JPG

203 Fit motor to bracket

Important Note:  To provide clearance to fit the Duet electronics in the base of the machine between 2 motors, one motor must be fitted to a bracket with the cable plug on the left hand side when looked at from the pulley end, and the other 2 with their cable plugs on the right hand side. See picture of 3 assembled motors below if you are not sure.

Align the motor with the plastic bracket (smooth side down for aesthetics). The first and second motors should have the cable socket on the right-hand side of the motor viewed from the pulley end (almost hidden in this picture).  Insert the 8mm capscrews and washers and screw in with the ball end of the 2.5mm hex key (in the order: screw head, washer, plastic bracket, motor). There is a hole in the printed part for the key to pass through. Make sure the screws go in straight - loosen and realign any screws that that have gone in at an angle. Tighten as much as possible with the ball end of the hex key, as there is not enough space to use the short leg.

Repeat for the other 2 brackets, but with the motor plug on the opposite side for the third one

204 Base assembly - parts needed

Motor bracket assemblies x 3

Frame extrusions 230mm long x 6

M4 x 10 button head capscrews x 24

M4 T-nuts  x 24

M4 flat washers x 24

205 Fit extrusions to brackets

Note: As shown in the pictures, the T-nuts must be fitted the right way round so as to fit and lock into the aluminium extrusions.

Fit 2 M4 x 10 button head capscrews with washers through the 2 bottom holes on one of the printed brackets from the inside. Fit M4 T-nuts to the bolts and tighten the 2 or 3 turns. Line them up as shown with the long sides of the T-nuts horizontal.

Fit a 230mm long horizontal extrusion over the nuts.

While holding the bracket and extrusion together, turn them over and do up the bolts with the long ball-ended leg of the 2.5mm hex key.

IMPORTANT: When tightening T-nuts it is essential to make sure that they rotate 90 degrees and lock into the extrusion slots. Giving the hex hey a fast twist initially can help this to happen. It is also better to tighten bolts which go into nuts that can’t be checked visually first - in this case the left-hand one. Once you feel that it is pulling the extrusion against the printed bracket, do up the second bolt on the right-hand side.

Check that the outer nut has rotated by looking down the extrusion channel.

You should always check that T-nuts have turned into the locked position by following the above procedure.

ANOTHER IMPORTANT NOTE:

Before tightening the bolts fully, you should always check that the cut end of the extrusion is butted tightly up against the printed bracket. Any gaps here will affect the build accuracy of your printer and give rise to calibration difficulties.

Check there is no gap here -------------->>

R211-tighten-second-corner.JPG

Repeat for the second bracket …….

R210-fit-second-corner.JPG

…...on both sides, …….

…… and the third, …..

…. both sides, …..

……. to complete the fitting of the lower extrusions.

Turn the assembly over and fit the upper extrusions in the same way.

R216-start-top-layer.JPG

Before tightening the bolts, double-check that there are no gaps at the extrusion ends.

R217-tight-corners.JPG

You can stand the assembly on edge and push down hard to close any remaining end-gaps and ensure the extrusion ends are firmly butted up against the brackets.

R218-push-to-tighten-corners.JPG

Finally use the short leg of the hex key to tighten the bolts fully. Be careful not to overtighten the outer bolts or they may split the plastic.

R219-final tightening.JPG

The completed base assembly may now be set aside while you get on with the top assembly.

R220-completed-base.JPG

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