3D Slices in Slicer not working as expected

[chrisjmulhall]

Project

I am making a wide-arch bodykit for my car. I designed it in Google/Trimble SketchUp and exported the kit as 8 separate unique pieces. I have .iges, .dwg, .obj and .stl exports of all these.

Wide arches highlighted on the carLeft and Right sides of the positive moulds

Manufacturing

The next step is to manufacture these from fibreglass. This will be achieved by fibreglassing over machined MDF moulds. The moulds are large, up to 900x600x100mm. This makes them difficult to machine with my Shapeoko 3, as I can not achieve the depth, width or length in most cases.

Instead I want to use Slicer to cut the job up into smaller pieces that I can make on my machine.

To begin with, I want to practice with the smallest piece and work my way up. The FLB and FRB pieces are the smallest:

Using Slicer on the .dwg of FLB

However the program fails and I get an error!

FLB Fail

So instead I try the .iges file and this time it works. I choose a custom material of 300x300x18mm MDF sheet, which is what I have bought for this project. 18mm means less slices and I have tools that can cut that deep. 

Looks ghastly on the regular slices though!

18mm Slices!

Unfortunately, when I switch modes to the "3D Slices" mode, my model disappears. It comes back if I click the rotate button in the top left (Next to untitled.stl) but disappears if I try to change the slice angle. There is also no button to export plans or anything. 

No options like before

Am I missing something? I have hit a roadblock with this and the project can't progress until I find a way around this.

I have attached the .iges file of the FLB part if you would like to try and replicate my issues.

[chrisjmulhall]

The file wouldn't upload with the main post. I have attached it to this reply instead.

[chrisjmulhall]

bump

[gmelantoni]

Hi Chris, 

Stacked slices are meant to create a section and produce an extruded slice (vertical). So what you get in the layout is the profile for you to cut. If the model is small and the slices are thick, I can see how the model looks like that.

I don't have a great explanation about why it disappears on the 3D slices. 3D slices don't show up in layout since the output is not a vector file. It's a 3D model of each slice to be exported as STL. 

[davebYYPCU]

I would not try to use Slicer with an intent to cut 18mm 3d walls.

Converting to Mesh seems to be loosing shape accuracy, there fore more cleaning and trimming, polishing, than Gcode will produce from Fusion models.

Use Fusion to slice your parts, with Split Body,

(done with the proper sketch, it's one feature per part) convert slices to Components for

Nester addin - to arrange on the table,

and CAM to post process the parts for Gcode.

Might help.....

[chrisjmulhall]

I understand the function of the stacked slices option. Unfortunately, I will lose too much definition to use that type of slice.

The 3D Slices is that type I need, but it does not seem exportable or save-able in any way. It just simply does not work. 

[chrisjmulhall]

Thanks for your reply. 

I am quite new to this software, and 3D modelling in general so please could you explain a little further for me?

For example, why would you not use 18mm 3D slices?

Losing accuracy is not super critical, I realise there are lots of small facets on my design (which are actually not required). Losing these is not a problem.

I tried to use the split body, but it wouldn't select my model. Eventually found a video that showed me how to convert from a Mesh to BREP which I was only able to do with my .stl exports, not dwg or obj. Now I have a BREP of my part, however when I use split body, I get an error saying there is no intersection with the body. In fact, there is no way to move the split body away from a face! Have I missed a trick here? Thanks for your time.

[davebYYPCU · Accepted solution]

My comments about mesh degradation - not using Slicer  - were my mistake,

modelling in Fusion is normally Breps.  I was thinking you had converted a Brep to a few types of Mesh, in the first place, and therefore I was recommending to stick with Breps, that are way better than Mesh bodies for finish and accuracy. 

18mm slices makes sense for 18mm stock, 

using stl - mesh,  or mesh converted to brep,  files for a fibreglass job on a full size motor vehicle does not make sense to me, but certainly could be done the long way round.

sorry for the confusion.... 

you will still need an answer - why the 3d output from Slicer didn't work as expected.

But not to leave you stranded, I converted the iges file to Brep, sliced it into 18mm pieces, 

over to you, file attached, 

[chrisjmulhall]

Wow thank you! I've just tried that and it works! This time, when I clicked "Export STL" from the top left drop down menu, it saved as a .zip containing every slice it made. 

Thanks a lot. Now to lay them out for the CNC mill..