Inkscape how to make a pressfit design

Understanding the laser cutter
The laser cutter can cut by burning away a little bit material. The laser follows the center of your vector line (drawing), burning away 0.1 mm on each side of the vector.

Beware! Different materials and different settings on the laser cutter can influence how much material is burned away.



The burning away 0.2 mm of material is a guideline, not a golden rule.

When your design is ready for laser cutting, first test and measure the difference before you cut out your whole design.

You will be wasting of a lot of time, effort and material if you assume it will just work out.

Inkscape example: sizes
Here you see a box drawn with the size of 50 mm by 50 mm.



But after cutting out this cube with the laser cutter, the actual size would be 49.8 mm by 49.8 mm as the laser will remove 0.1 mm from all sides.

Stoke vs. Fill
Open up the fill and stoke menu by going to object > fill and stroke.

In this menu you can change the fill of you object and the thickness of your line width around your object. If you want to design something where scale matters (like with press fit) it is recommended to draw with a fill on you object only. Because if you design a shape with a line with set, inkscape includes the line width in the size.

Example stroke or fill
Let's draw a box of 50 by 50 mm, but also set a line width to 2 mm.

Now if you look at the object with the box tool, you can still see that it still is 50 mm.



But if you use the black mouse tool to select your object, you can see that the line width is actually included in the size. Hence a size of 52 x 52 mm.



Step by step in inkscape
Let's say we want to make something like in this image. Cutting out 2 pieces with a slot, that (press) fit together.



1. Create a large box (50 x 50 mm)



2. Measure you plate of material.



The MDF you see in the photo is a standard plate of 4 mm thick, but if you measure it you can see that it's actually 4,13 mm.

Measuring really matters!

3. Create a smaller box that overlaps the first, and give it a width of your measured plate.



4. If the smaller box is behind the bigger box you can let them swith places by selecting the shape you want to move to the front, and go to Object > Raise to Top



5. To get the smaller box nicely centered. Go to Object > Align and Distribute.

First select both shapes, then choose in the Align and Distribute menu 'biggest object' and click on 'center on vertical axis' button.



6. Now let's subtract the blue box from the red one to finish the design. Select both shapes. Go to Path > Difference.



Now you design is ready, final step is to prepare it for the laser cutter.

Offsetting the line
7. Select your design and and go to Object > Fill and stroke



8. Go to the stroke paint tab and set a color. (click on the box)

9. Then go to the stroke style tab and change the line width to 0.2 mm



10. (While your object is still selected) in the menu choose Path > Stroke to path

11. (While your object is still selected) next select Path > break apart.

Your object should now have adopted the color from your stroked line (in my case blue), and (if you zoom in) you should see 2 dotted lines around your object.



12. (While your object is still selected) go to the fill tab of the fill and stroke menu. And turn off the fill by clicking on the X.



13. Then set the stroke again in the stroke paint tab. (click on the box).

14. Back to the stroke style tab and set the line width to 0.01 mm



15. Deselect everything by clicking outside your shape (no more dotted lines)

16. Now select the innermost line of you object and delete that line (right mouse button).



Your object is now offset by 0.1 mm to the outside.

Beware. If you design has a hole in it, then you should offset that line to the inside. Steps are the same but delete the outside line then instead.

17. Now if you would cut out this shape twice with the laser cutter, they should fit together nicely.

Example of press fit project

 * [Example Press-fit-Construction-Kit project]