Need help with a model modification (cookie cutter!)

[flashpass]

Hello,

I'm fairly new to Fusion360 and have been fussing with what seemed like would be a really simple task. I recently created a 3d printable cookie cutter and put it up on Thingiverse. Originally it was created in TinkerCAD, but since I'm trying to learn Fusion360 I would really like to know how this can be done. Basically the cutter part of the model is 1mm thick, and because most of our nozzles are .4mm, there would often be a gap in the middle of the cutter where dough would squeeze into. So, I basically wanted to shave off .2mm (by removing .1mm from both sides of the cutter inward), and leave everything else the same.

What steps would you take to make this change? I tried a lot of combinations of cutting in half, offsetting edges/faces, etc. Any help would be greatly appreciated!

http://www.thingiverse.com/thing:2106377

[LMD001]

@flashpass

Hello,

Welcome to the Fusion 360 Community.

In the following thread there is a very good Screencast on how to convert a Mesh to a BRep.

https://forums.autodesk.com/t5/design-validate-document/converting-stl-to-model-object/m-p/6563247#M...

Best regards,

Ludo

[flashpass]

Hi Ludo, thanks for the response. I actually didn't have any trouble with that conversion (once I learned how to do it). I'm having trouble on what steps to take after converting.

Thanks again.

[LMD001]

@flashpass

Hello,

If I had to do this I would retrace the cookie cutter with a spline and rebuild the model in Fusion 360, in my opinion it will you take far less time than to modify the STL the result will be difficult to edit.

It took me 4 minutes to build this model, (I know, not exactly your unicorn).

I will try to retrace the unicorn later today and provide you the model.

Best,

Ludo

[davebYYPCU]

There are a few things to do and many ways to get there, if it were me, shaving 0.1m off both sides is too hard for the benefit it may give

I would create a Offset Plane on the rim section lower face - as you use the cutter.

Split Body with that Plane, (makes a separate rim and cutter body)

then create a Sketch on the same plane, and project the inside wall of the cutter body.

Hide the cutter body.

Use Sketch offset to offset that projected set of lines, out by 0.8mm (size as desired)

and extrude the new profile, using join (to the rim) as desired,

Save / Export etc.

[LMD001]

@davebYYPCU

Hello,

Agree that is a very good way to reproduce the curve, tried that approach also, but the fillets on both sides of the base gave me problems.

As you wrote, many ways to get there.

Best,

Ludo

[LMD001]

Hello again,

Had a better look, OK no fillets, must get a better monitor (or new glasses).

The method @davebYYPCU proposed is the better way to go then.

Best,

Ludo

[flashpass]

Thank you for the explanation! I'm happy to say that I actually started going down that same solution, but then got stuck. I split the cutter and the base apart into separate objects. After that I did some offsets in sketch mode by selecting one of the inner outlines of the base cutout, and extruded that new sketch back up. The problem I'm having now is that there is a .1mm gap between the base and the cutter! So is there an easy way to fill the space in the base and then join the cutter back to it? 

Also I wasn't aware of the "project" tool. I'll take a look and learn about how it works (it's difficult to search for "project" 🙂 ).

-Daniel

[flashpass]

Thanks for taking a look. Once I get the core shape down and printing as desired, I will probably end up adding some fillets/chamfers! For now I'm part way there, just missing a few bit s of information I feel to get the final thing produced.

[flashpass]

Okay, so I figured out a very simple way to solve this - although I'm not really happy with it because I feel like I failed in modifying it the way I wanted previously. I would still like input on how you would accomplish the task I mentioned above (repairing the hole in the base shell, and joining it with the cutter shell body).

So how did I do it? I simply extruded the face on the very bottom of the base up 2mm, and then extruded the very top face back down 18mm. In retrospect once I got the top face, this all should have been so obvious.

-Daniel

[davebYYPCU]

I am a little confused, after you found the 0.1mm airgap,

You extruded the new wall, leaving a gap?

Ok, You can extrude 2 directions up and down,

separate distances,

to make the join

eg Extude up 10mm same dialogue extude down "to object" select the rim surface.

Don't be hard on yourself, there are many ways to get things done.

[flashpass]

Sorry I guess that wasn't super clear. End-to-end, these were the steps I took (if I get rid of all the messups!):

1. Split the cutter and base apart using a flat plane moved up 2mm. This left a curved cutout in the top of the base where the cutter used to be.

2. In Sketch mode, selected the edge of the cutout in the base, and then offset it twice (once at .1mm, and another at .9mm) to produce the new cutter wall paths.

3. Extruded the new cutter paths up (which is now ~.8mm thick/across).

4. Since I couldn't modify the base properly and join it with the new cutter shells I just extruded - I simply selected the very bottom face and extruded up 2mm, and selected the very top face and extruded down to the top of the base. This produced the final cutter bodies I could just merge together.

Hope that doesn't make things more confusing. I am genuinely curious how I could have patched the big cutout in the base (shown in the picture), and merged/joined it with the top cutter bodies.

[davebYYPCU]

Ok, makes sense now,

To fill the hole in the rim you can extrude the top of the rim back to the bottom of the rim and join.  Will fill the cavity in that process.

I wasn't sure if you knew about extrude in two directions after reading what you said, but now I see that you shaved 0.1mm off both sides of the cutter wall, as intended.

[flashpass]

Sadly I just reprinted and it didn't fully solve the problem. I think I will need to put some sort of chamfer on the top surface to force printers to print a couple single layer widtrh lines on top to fill/close that gap...

[thburn]

Hi,

did you ever think about changing the settings of your slicer instead of changing the model?

Even if the nozzle diameter is 0.4mm you can set up a print width of e.g. 0.33mm. This will make the printer extrude less filament and this will cause a thinner print width than the nozzle diameter.

I work with Simplify3D and I used 0.33mm for my 0.4mm nozzle on my Ultimaker 2.

If I print a wall at thickness of 1.0mm Simplify3D creates 3 paths of 0.33mm which adds up to around 1.0mm without any gap and they come out very nicely!

May it is worse to try 😉