Week 10 - Mechanical and machine design

Goals

mechanical design:

• design a machine that includes mechanism+actuation+automation+application
• build the mechanical parts and operate it manually machine design:
• actuate and automate your machine

Teammates pages

We worked together with Stephane and Lauriane. Stephane was in charge of the automation and Lauriane made the parts for the X axis

See Stephane's contribution page

See Lauriane's contribution page

Project description

Goal: Make a X Y pen plotter

The general design is inspired by the following video:

Mechanical components

For the motion our main mechanical components are:

• 2 aluminium extrusions for the axes
• 2 6mm belts
• 2 pulleys
• 7 wheels

We also used a lot of screws (M3 and M5), bolts

Homemade parts

3D printed PLA parts

• Y axis left foot which supports the Y belt pulley
• Y axis right foot which supports the Y stepper motor
• X axis motor holder
• X axis pulley holder
• pen holder male rails
• pen holder female rails
• pen holder ring
• spacers

Waterjet cut aluminium parts

• Y axis charriot (2 platforms) which supports the X axis
• X axis charriot, which is the fixed part of the pen holder
• moving part of the pen holder

Electronics

• M5 stack

Main individual contributions

• Y axis left foot (motor holder)
  • CAD
  • printing tests
  • printing final parts
  • assembly
• Y axis right foot (pulley holder)
  • CAD
  • printing tests
  • printing final parts
  • assembly
• Y axis charriot
  • CAD
  • laser cut tests
  • waterjet aluminium cutting
  • assembly
• X axis charriot
  • very small CAD adjustments (original design of Stéphane)
  • waterjet cutting
  • 3D printing

Individual work on CAD

We all collaborated on the same fusion project. The first step was to collect all 3D models of the existing material we would use.

Imported designs

I mainly sourced these models directly from our parts supplier Systeal. It provides mainly the aluminium extrusions, and also parts that can ben combined easily with the extrusions: belts, wheels, pullies, hammer head nuts.

• Profilé aluminium V-SLOT 20x40 fente 6 mm

• Roue V-Slot Solid XTREM

• Kit de roue libre pour poulie

• Ecrous marteau M5 - fente de 6 mm

• Courroie crantée GT2 6mm

For each product you can find a description with a 3D View which redirects to the website 3dcontentcentral to download the parts in the desired format (login?). I thus downloaded all the .STEP

I also used GrabCAD for the following parts (you need to create an account):

• GrabCAD is unavailable in your location

• Pulley GT2 - 20T B5 | 3D CAD Model Library | GrabCAD

First tests left and right feet

I carefully created as many user parameters as I could to be able to modify my design quickly if the tests were not well dimensioned from the start.

The first tests were a bit too loose so I changed my footloose parameter

Improved feet designs

I first draw a sketch with a spline line, but finally changed it for rectilinear lines, then filleted the shapes.

I also added perpendicular feet to screw the parts if necessary.

I adjusted my design with chamfers, then when I was satisfied with my right foot I mirrored it. Unfortunately the chamfers didn't match correctly. I then had to remove them and rechamfer it.

Charriot platform

Wheel and extrusion assembly tries

Pen holder adjustments for waterjet cutting

In fact I will cut this part with the waterjet, so no need to chamfer the design.

The holes were good for a screw to pass through but we want to fillet them, so we need a smaller hole.

Pen holder ring modification

We will screw the ring at the same time as the 3D printed rails behind.

Individual work on 2D cutting

MDF Laser cut tests

Aluminium waterjet parts

It was the opportunity for me to get more familiar with the OMAX waterjet cutting machine. I'd say the more sensitive aspect is the software parts, in particular:

• problems in the design when .svg imported
• problems in the dimensions when .dxf imported
• setting the correct autopath and starting point to have the waterjet on the correct side of the hole

The result is very nice and sturdy!!

Here are the parts for the pen holder charriot:

3D prints

The feet designs aren't great for 3D printing, as I couldn't find any great orientations avoiding printing supports.

Also I printed most of the parts with a quite low infil because I was in a iterative process and not ready to waste material and time for more durable parts.

I finally printed the feet and the pen holder rails in white matt PLA, and the ring in light grey PLA.

I put metal M3 inserts in the ring holder using a solder iron (the textured part of the inserts should be downside).

Assembly

Pictures

Files

• 3D designs

• Waterjet cutting 2D designs

• Imported component CADs