Mendel90

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Mendel90

Release status: Experimental

Description	A Mendel with flat sheets at 90 degree angles
License	GPL, Creative Commons
Author	User:Nophead
Contributors
Based-on	Prusa Mendel
Categories	Development
CAD Models	Thingiverse
External Link	HydraRaptor: Mendel90

Mendel90 is being designed by Nophead to replace many of the threaded rods and printed parts of the [Prusa Mendel] with flat sheets, either MDF or Acrylic.

Advantages

Compared to the Prusa Mendel, which it is based off of.

• Stiffer, especially in the X Direction, so it can go much faster without vibration
• Much less calibration and jigging required; if your holes are in the right places, your rods will be parallel
• Can be drilled with a paper template to make sure all holes are perfect
• Sheets are usually straighter and flatter than rods, as they are thicker and much wider
• All the OpenSCAD files are fully parametric; you can set all the parts to whatever sizes you want and easily increase the build area
• Everything is mounted on one of two planes, so it's all flat
• Frame is held together throughout the machine, instead of just at the corners, so much less warping
• Less vitamins
• Open design, allowing it to be worked on easier and mostly dissasembled without falling apart
• Z axis motors are at the bottom, so that the couplings don't need to support the weight of the X axis
  • This means the Z couplings can be smaller, and therefore Z smooth rods closer to the threaded rods, increasing stiffness
  • The center of balance is also lower, making it more stable
• Less printed parts, so it can be printed easier and faster
• Parts are ribbed to maintain strength and decrease print time
• Ribbon cables are used to prevent cable tangling and friction
• Rectangular, so it can be shipped and put in Heated Build Chambers easier.
• Uses LM8UU bearings
  • Uses 10 instead of 12, so only one package is needed

Disadvantages

• If you drill a hole wrong, it is much harder to fix than to adjust a nut on the Prusa Mendel
• Less room for adjustment-only a few mm
• Harder to expand to a larger build area once built
• MDF expands with heat and moisture, and Acrylic cracks-MDF could be coated with Epoxy
• OpenSCAD files have not been released as of March 4, 2012
• More volume of vitamins-sheets are larger than rods
• Probably heavier and harder to ship
• More types of screws
• Louder because sheets act as soundboards
• Fewer bearings might make it less accurate

Development

Nophead says he will put his OpenSCAD files on Github, but they are not up yet.

Bill of Materials

Printed Parts

Required

Quantity	Description	File	Diagram
10	Fixing Blocks-For joining sheets	stl	pic
4	Z Coupling	stl	pic
2	Pulley	stl	pic
1	Bar Clamps	stl	pic
1	X Motor Bracket	stl	pic
1	X Idler	stl	pic
1	X Carriage	stl	pic
1	Y Motor Bracket	stl	pic
1	Y Idler	stl	pic
1	Y Bearing Mounts	stl	pic
1	Y Belt Anchors	stl	pic
1	Z Motor Brackets	stl	pic
1	Z Coupling	stl	pic

Modified Wade's Geared Extruder

Quantity	Description	File	Diagram

Optional

Quantity	Description	File	Diagram
1	Fan Guard-If you have a fan	stl	pic
1	Cable Clips	stl	pic
4	Z Pointer	stl	pic

Non-Printed Parts ("vitamins")

 1 Acrylic sheet 468 x 432 x 10
 2 Acrylic sheet 170 x 324 x 6
 1 Acrylic sheet 224 x 224 x 6
 1 Acrylic sheet 468 x 324 x 6
 4 19mm bulldog clip
 3 Ball bearing 4 x 13 x 5
 3 Ball bearing 8 x 22 x 7
22 M3 cap screw x 10
22 M3 cap screw x 16
17 M3 cap screw x 20
 4 M3 cap screw x 25
 2 M3 cap screw x 30
 2 M3 cap screw x 45
 4 M4 cap screw x 20
 2 M4 cap screw x 40
 1 9 way D plug
 1 9 way D socket
 3 M3 grub screw x 6
 1 glass sheet 214 x 202 x 2
 5 M3 hex screw x 16
 2 M4 hex screw x 20
 2 M4 hex screw x 50
 1 M8 hex screw x 60
10 LM8UU
 5 NEMA17x47.5
 1 PCB bed
 1 polypropylene strip 373mm x 17mm x 0.5mm
 1 polypropylene strip 320mm x 27mm x 0.5mm
 1 polypropylene strip 275mm x 29mm x 0.5mm
38 M4 pan screw x 12
24 M4 pan screw x 16
 1 Rod 8 x 22
 3 Rod 8 x 275
 2 Rod 8 x 382
 1 Rod 8 x 428
 2 Studding 8 x 211
 2 Tubing OD 7 ID 5 x 16
12 No2 pan wood screw x 13
 6 ziptie 87
 1 belt T5x6x674
 1 belt T5x6x861
 4 hex pillar M3x20
 3 microswitch
 6 nut M3
 2 nut M4
 3 nut M8
45 nyloc nut M3
 6 nyloc nut M4
 2 rubber washer M3 x 9.7 x 1.5
 1 spring 12 x 0.75 x 10
 2 spring 7 x 1 x 10
18 star washer M3 x 7 x 0.5
53 star washer M4 x 9 x 0.9
12 washer M2.5 x 5 x 0.5
79 washer M3 x 7 x 0.5
78 washer M4 x 9 x 0.9
 4 washer M5 x 20 x 1.4
 1 washer M8 x 16 x 1.5
 2 wingnut M4

See Also

Category:Development