Mendel frame

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Revision as of 16:18, 8 December 2009 by Adrianbowyer (talk | contribs) (Assembly)
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Mendel Build Documentation

You may find the Mendel assembly data sheet useful during assembly.

Frame sides


Total # of assemblies: 2

Frame-vertex_6off 3 6 RP
Stud-frame-side 3 6 Studding
M8 washer 14 28 Fastener
M8 nut 14 28 Fastener
z-leadscrew-base 1 2 Assembly

Printed part



Triangles are equilateral (J1 applies to all sides).

In addition: each assembly needs either a Z-motor or Z-tensioner bracket, as shown in the diagram. Tensioner should pair with the leadscrew base which has the opto installed.

Check the Mendel assembly data sheet for bar/stud lengths and jig/inspection distances.


Frame ends


Total # of assemblies: 1

Name Qty/assembly Total Qty Type
z-bar-top-clamp_4off 4 4 RP
M4x40 bolt 4 4 Fastener
M4 nylock 4 4 Fastener
M4 washer 8 8 Fastener
Stud frame end top 2 2 Studding
Stud frame end 4 4 Studding
Stud z base beam short 2 2 Studding
Stud z base beam long 2 2 Studding
M8 nut 68 60 Fastener
M8 washer 64 56 Fastener
Y motor bracket 1 1 Assembly
Y idler bracket 1 1 Assembly

RP parts



Note extra nuts and washers on the upper two studs of the bottom frame ends. Check the Mendel assembly data sheet for bar/stud lengths and jig/inspection distances.


Installation of X-axis


Total # of assemblies: 1

Name Qty/assembly Total Qty Type
z-bar 2 2 Bar
x-axis 1 1 Assembly
z-leadscrew 2 2 Assembly
M4x12 bolt 6 6 Fastener
M4 nylock 6 6 Fastener
M4 washer 12 12 Fastener
z-belt 1 1 Belt


Roll the frame onto its back, and position the x-axis into the top end. Thread the z-bars through the leadscrew base, x-axis and top-clamp. Fasten z-bars.


With the frame still on its back, slide the partly assembled z-leadscrew through the leadscrew base and screw into the M8 trapped nut on the x-axis. Screw in until bearing sits flush in leadscrew base. Fasten with caps.


Complete the leadscrew assembly with the parts which were temporarily removed in the initial assembly. Repeat for other side.


Keep frame on its back. Whilst still keeping the x-axis at the top end of the leadscrews, rotate the leadscrews until the x-axis is approximately square. Better calibration will be achieved later, however, both leadscrews should turn fairly freely. Attach the z-belt. How taught should it be? The answer is: as lose as possible without backlash. Tighten it too tight, and turn the Z stepping motor by hand. You should see both Z screws rotate, even when you turn the motor by a single stepper step (you can feel the detent). Now gradually slacken the belt so that you are at the limit where it still behaves like this: as you turn it one detent, then back again, both Z screws turn forwards and backwards.


Leave assemblies in their current position for the next phase.

Fitting the bottom circuits


Total # of assemblies: 1

Name Qty/assembly Total Qty Type
circuit-board-spacer-m4_2off.par 2 2 RP
y-bar-clamp_10off.par 2 2 RP
m4-nylock.par 4 4 Fastener
m4-washer.par 8 8 Fastener
m4x40-cap.par 4 4 Fastener
Bottom-circuit-board 1 1 Assembly

RP parts



Position the board over the larger gap of the base, nearest the y-motor, with the XLR and USB sockets facing out (1). Use the spacer and clamp assembly attach to the frame (2).


Put the frame back in its upright position. Leave the x-axis at the top, out of the way for the next phase.

Installing the Y-axis


Total # of assemblies:1

Name Qty/assembly Total Qty Type
y-bar-clamp_10off 8 8 RP
m4x40-cap 8 8 Fastener
m4-washer 16 16 Fastener
m4-nylock 8 8 Fastener
y-belt 1 1 Belt

RP parts



Loosely install the y-bar clamps and y-bars. Set J3 so the bar clamps are in approximately the right place. (Bottom circuit boards hidden for clarity)


Now retract the y-bars. Position the y-chassis and thread bars back through the y-chassis. Re-confirm J3 and fasten the y-bar clamps fully.


Note that if you build the base etc from 4mm ply or MDF the rectangle that forms the tray for catching extrudate at the beginning of a build is held on with 15 mm M4 cap screws. But if you make the base etc from 6mm (which will give a better sturdier machine, and so is recommended) you will need 20 mm M4 cap screws for this.

Fit the y-belt


Installing the bed


Total # of assemblies:1

Name Qty/assembly Total Qty Type
bed 1 1 Sheet
m4x40-cap 4 4 Fastener
m4-nylock 4 4 Fastener
m4-washer 8 8 Fastener
bed-spring 4 4 RP

RP parts

RP spring design may vary



Fit bed to chassis trapping the springs between the bed and the bearing brackets.


Fitting the top circuits


Name Qty/assembly Total Qty Type
circuit-board-bracket-m3_4off.par 4 4 RP
m3-capx20.par 16 16 Fastener
m3-nylock.par 16 16 Fastener
m3-washer.par 32 32 Fastener
Top-circuit-board 1 1 Assembly

RP parts



Wind x-axis down to the bed, as this will get in the way. Wind by lifting the frame up to pull the z-belt. Do not let nozzle closer than 1 cm to bed – if the bed slides around before calibration it may damage the nozzle by scraping against it. Position circuit board at the top of the front side, as high as possible (1). Use four bolts per clamp and fasten securely as this element improves chassis rigidity (2).



Congratulations! That's the assembly complete, we hope you enjoy your new 3D printer! Before printing anything don't forget to square the axes.

Back to Mendel mechanical construction root.