Support pattern for flat surface , efficiency question

[jochen_matthijs]

Hey all!

First of all, I'm very new to CAD & 3D printing.

Today I was trying to 3d print a box, but as I printed the test piece I noticed that a big flat surface isn't the most rigid.

So I drew a square support pattern in the lid of the box.

 To draw this I first calculated a square that would fit in the lid, I decided to do the length of the lid divided by 10.

I tried to do a rectangular pattern to fill the whole surface but I couldn't get them to basically share a border, so I drew them all by hand.

Then I offset every single line once by 1mm (clicking them all 1 by 1) to then do this all again to offset it by -1.

After all that i had to delete every single middle line to be able to extrude the pattern.

My question is, what would be the most efficient way to draw a support structure like this in any shape?

I couldn't find any video that would apply to my case.

Thanks a lot in advance

[etfrench]

Extrude one rib at the center. Rectangular pattern the rib feature. Copy and rotate the copy of the rib 90 degrees. Rectangular pattern that rib feature.

p.s. Instead of deleting your center line, change it to a construction line (Normal Construction).

[jochen_matthijs]

Well... that's very simple no clue how I didn't think of it..

Is there any way to automatically calculate the best shape and size for a given surface?

[Bunga777 · Accepted solution]

I would use the web.

Gaps and spacing are appropriate; I don't think there is any need to be particular about dimensions when it comes to the web.

Thus, including the sketch, it takes four steps to complete.

I have attached a sample file in case you are interested.

[jochen_matthijs]

Holy hahaha! 

Okay thanks A LOT, I did this in about 3 hours of struggling, I did learn a lot that's kind of why I simply didn't ask it before I started the project!

Thanks!!

[etfrench]

Even easier is to use Gyroid or Cubic infill in the slicer.  I usually use 31% infill and 3 or more perimeters for max strength.

[jochen_matthijs]

Can you explain further? I use Ultimaker Cura.

[etfrench]

Cura has both Gyroid and Cubic infill patterns.  Each of them offset each infill layer slightly so the infill is strong in X, Y, and Z.  The infill will also be stronger than adding ribs.  If you still want to add ribs, add them below the surface.  Do this by creating the ribs as a separate component, then use that component as a print modifier in Cura.  This will give your box a flat bottom.