Knurled pattern on a flat surface

graham_mills · August 2017

Hi,

I'm trying to create a knurled pattern on a flat surface. It's a 5mm thick sheet of aluminium with grooves machined in the top (on the x and y axis), creating a pattern of little flat-top pyramids. This will be to provide grip on the finished product.

So far I've tried: making 2D pyramid pattern on the sides and extruding (with Remove) across the surface. This works in one direction but when I try to make the same pattern perpendicular to it the sketch fails as it's interfering with the first extrusion. I tried creating new planes on which to create the pattern and then extruding (Remove, Through all) across, but same again. I even tried making a simple pattern of one groove, extruding it into a V-cut, then using Linear Pattern to copy the groove across the rest of the surface. Problem with that is that as soon as I select the groove as an entity to use in a Linear pattern, the word 'Direction' appears in red and won't let me tell it which direction I want the pattern in...

The final thing I tried was this: creating one single small pyramid, then spreading it across the surface using a Linear pattern... same problem again with Direction showing up red with no options.

Image: https://us.v-cdn.net/5022071/uploads/editor/zv/6xwn0pexqk4e.jpg

I found even just creating this little pyramid difficult. I'm still at the stage where I'm struggling with things that more experienced users wouldn't even need to think about.

Any idea how I can make this knurled pattern on the surface?

Cheers.

brian_jordan · August 2017

Quick and dirty and not to scale but a linear patern of "V"s along the front and side faces followed by extrude remove seems to do it.

https://cad.onshape.com/documents/76895f360aefec55fd25a895/w/8631a28f306a2b27b5899824/e/c9c44ffd264893e054519a0b

emagdalenaC2i · August 2017

Here is another option
https://cad.onshape.com/documents/adb788848a7ebf78a79f03b5/w/dc21daf2c68b97ebebeea49c/e/cba74d6d1099bd1ac24a7ab3

brian_jordan · August 2017

Quick and dirty and not to scale but a linear patern of "V"s along the front and side faces followed by extrude remove seems to do it.

https://cad.onshape.com/documents/76895f360aefec55fd25a895/w/8631a28f306a2b27b5899824/e/c9c44ffd264893e054519a0b

graham_mills · August 2017

Hi Brian,

OK, I'll give it a go and let you know how I get on! Thanks for the reply, much appreciated.

emagdalenaC2i · August 2017

graham_mills said:

Hi,

The final thing I tried was this: creating one single small pyramid, then spreading it across the surface using a Linear pattern... same problem again with Direction showing up red with no options.

Any idea how I can make this knurled pattern on the surface?

Cheers.

I think that the direction showing up red because you didn't set one... Just select the direction textbox and select an edge in the direction you want or a plane perpendicular to that direction.

emagdalenaC2i · August 2017

Here is another option
https://cad.onshape.com/documents/adb788848a7ebf78a79f03b5/w/dc21daf2c68b97ebebeea49c/e/cba74d6d1099bd1ac24a7ab3

philip_thomas · August 2017

Just in case no one else says it - it doesn't matter what CAD system you are using, the vendor would say "please don't do this!"

This kind of activity is extremely 'expensive' (slow) to rebuild and at scale represents significant increase in complexity to the total edge count.
If you HAVE to do this (because for instance you are going to 3D print this), please either suppress the features immediately after exporting the STL or even better, have the fully featured part on another branch.

Think about this - a complex casting might have 200 edges - just the simple example above has 1216 !!!
I realize that edge count is only a proxy for geometry complexity, but you get the idea.

Good luck!

graham_mills · August 2017

emagdalenaC2C - I sussed the whole 'direction' thing and managed to make that same way work. I also got Brian's suggestion to work. Quite pleased that I managed to get sense out of both approaches having initially got nothing from either. Thanks to you both.

Philip - that's a very good point. My computer is *really* slow anyway but I noticed it almost ground to a halt when I put the patterned surface on the shape it was originally designed for. My reason for doing it is that eventually I'd like to have the pieces CNC cut in aluminium and the machining will need to be done to the faces (they're car pedal covers; the brake and clutch need some 'grip'). Whether I could leave this off the finished CAD model and have the patterned machined another way might be a better way of doing it.

Cheers all.

philip_thomas · August 2017

@graham_mills - Looks like you're on the right path

Re 'your computer' - The only hardware dependent performance metric is shading speed.
If you go to cad.onshape.com/check, you will get a sense of how fast your graphics card is.
(<10 million triangles per second = slow. Fastest machines are around 350 million triangles per second)

The factors contributing to open time are;

Time to process on our end (rebuild model and facetize)
Time to pass new/different triangles
Time for your machine to render them

The factors contributing to interactive performance (no re-calculation of sketches or geometry)

Ping time

Have fun.

Knurled pattern on a flat surface

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