Inmoov Head Design Modifications

Cool, the files downloaded , thanks Nomad

Hi RoboHappy,

Great to hear the files downloaded successfully! If you run into any more issues or have questions about implementing these modifications in your InMoov head project, feel free to ask.

Happy building!

hello inmoov roboteers

some updates . first skull with nut in place and use some hot glue , nothing els /

next i still have some contact between parts .

im trying this . 1 mm cut off on the outside and ad 1 mm on the inside frame .  also a cut off 1 mm side pannels .im test printing now .

i checked avery part angle fo figur out were this come from .

it started when i put the side pannel on . so im gessing the contact might be the cause . more updates later .

Great progress - nice photos and good troubleshooting. A few focused tips and next steps to help eliminate the contact and get reliable fits.

Summary of likely causes

• Print tolerance vs CAD tolerance - printed parts often come out slightly oversized (or undersized) depending on slicer/printer settings.
• Warping/print orientation - side panels or long thin sections can shift as they cool, causing interference when assembled.
• Mating-feature interference - small misalignment or a raised corner/pin will cause contact when the side panel is added.

Quick checklist you can try right now

1. Identify exact contact point

   • Assemble slowly and see where the parts first touch. Mark the spot with a pencil or masking tape to confirm the interference area.

2. Measure printed dimensions

   • Use calipers to measure the printed mating dimensions (pins, slots, holes) and compare to the STL dimensions. That tells you whether you need positive or negative compensation (shrink or enlarge).

3. Do a small test print (coupon)

   • Print a small slice of the mating area (10-20 mm) with the same settings. It’s fast and confirms fit without printing the whole part.

4. Try changing print orientation

   • Rotate the part so mating surfaces are printed on the bed or oriented to minimize overhangs. This often reduces warping.

5. Slicer tweaks (fast tests)

   • Reduce/extrusion multiplier slightly (3-5%) if parts are oversize.
   • Lower print temperature or enable better cooling to reduce filament squish that increases dimensions.
   • Print slower or thinner layers for more accurate tolerances.

Design fixes (recommended)

• Small clearance increments: don’t jump to 1 mm unless you want a loose fit. Typical clearances:

  • Press-fit (tight): 0.1-0.2 mm
  • Sliding fit: 0.2-0.4 mm
  • Loose / easy assembly: 0.5-1.0 mm
    Start by changing 0.2-0.5 mm and test.

• For the outside shell interfering with inner frame:

  • Reduce the outer shell by 0.2-0.5 mm (offset inward) or add 0.2-0.5 mm to the inner frame mating surfaces.
  • Add chamfers or fillets to edges so they "ramp" into place instead of hitting flat-on.

• Use alignment pins / locating features:

  • If the side panel is shifting during assembly, add small alignment pegs & holes (0.5-1.0 mm interference) to force correct positioning.

Hardware ideas

• Nuts: hot glue works for temporary fixes. For a stronger, repeatable solution use heat-set inserts or M3 hex nuts captured in a recess sized for the nut + ~0.2 mm clearance.
• Jaws/hinges: ensure hinge pins are straight; if the hinge area gets heat during gluing, parts may warp - keep assembly cool while glue cures.

How to edit the STLs

• Easy tools:
  • Meshmixer (free) - good for quick boolean/offset edits. Use a scaled negative/positive copy to create clearance (boolean difference).
  • Fusion 360 (free for hobbyists) - best for precise offsets (modify -> offset) and parametric changes.
  • Blender - can do it with Solidify modifier or boolean operations.
• If you want, I can adjust the STL(s) for you. Tell me:
  • Which file(s) to edit (jaw / frame / eye support)
  • Desired clearance (e.g., +0.2 mm on inner frame, -0.2 mm on outer skin)
  • Material (PLA / PETG) and nozzle size (0.4 mm) so I can match typical printer tolerances.

If you prefer slicer-only fixes

• Use scaling on the axis that matters (X/Y) but be careful - it affects the whole part. Better to edit the STL if you need localized changes.

Follow-ups

• Which filament are you using (PLA / PETG / ABS)?
• Printer model, nozzle size, and layer height?
• Do you want me to tweak one of the STL files (and by how much clearance)?

I can make small STL adjustments and re-upload test files if you want - just tell me the preferred clearance and which part to start with.

@athena

i have found the main problem why the hole head is not horizontal , and also diff to put all parts together . i fix the frame and wil print a test . frame touching the sides is solved . what do you think of this ?

here a short video .

https://www.youtube.com/watch?v=yaBN_BxU3DE

Nice work finding the root cause - that’s half the battle. Thanks for sharing the update and the video link.

A few targeted comments and next steps to verify the fix and get reliable assembly:

1. Quick confirmation

• Can you confirm the issue was the frame being forced out-of-flat by the side panels (so once you corrected the frame geometry the head sits horizontal)?
• If the test print is done, please upload a few close-up photos (or a short clip) of the head sitting on a flat surface and a photo of the assembled inside/outside seams so I can confirm alignment.

2. Assembly & test checklist (run these before printing more full parts)

• Dry-assemble without glue/fasteners to see where first contact occurs - mark the spot with tape or pencil.
• Measure mating dimensions with calipers and compare to the STL (if possible). This tells whether you need positive or negative compensation.
• Print a small "coupon" (10-20 mm section) of the problematic mating area to quickly test fit before printing the whole part.
• Verify the flat plane: place the frame on a known-flat surface (glass or machinist plate) to check twist/warp.

3. Small design/tolerance suggestions

• Typical clearances: press-fit 0.1-0.2 mm, sliding fit 0.2-0.4 mm, loose/easy assembly 0.5-1.0 mm. Start with +0.2-0.3 mm where parts touch.
• Add chamfers/lead-ins on mating edges so parts ramp into place instead of hitting a hard corner.
• Consider small alignment pins/holes (0.8-1.0 mm) to force correct location when panels are attached.
• For captured nuts, heat-set inserts or a nut pocket sized ~nut +0.2 mm give repeatable results (hot glue is fine for quick tests).

4. Slicer tweaks you can try quickly

• Cura: Horizontal Expansion (negative value to shrink outside dimensions) - useful if outer shell is tight.
• Extrusion multiplier: reduce 2-4% if prints are oversize.
• Lower print temp / increase part cooling to reduce "filament squish."
• Print orientation: place mating faces on the bed if possible to minimize warping.

5. If you want me to edit the STL(s)

• Tell me which part(s) to adjust (frame / side panels / jaw hinges / eye support).
• Tell me target clearance (e.g., add 0.25 mm to inner frame or subtract 0.3 mm from outer shell).
• Tell me your filament, nozzle size (e.g., PLA, 0.4 mm nozzle), and layer height so I can match tolerances.
  I can make small STL adjustments and re-upload test files for you.

6. Useful reference

• 3D Parts / upload docs on the site: https://synthiam.com/Support/ARC-Overview/Project-Menu/3D%20Parts

Next step: did the test print show the frame now sitting horizontal? If so, upload pics or tell me which part you want tweaked and by how much and I’ll edit the STL for a quick test.

@athena

as you can see in the video the horizontal was off  allreddt by atleast 1,5 MM  it changes when tighten the screw . i allreddy corrected the frame ,

nice flat heads of the frame .

lets print it , then i post the result .

@athena

some pictures how i checked all parts . first thing i notest all parts looks spot on . i used all colors , averything was perfect , so it had to be something els . why the left side ? wel that arm is a little shorter then the right arm of the frame, as seen in the video .

then i notest this . the lower back skull was off .

the new lowbackskull is almost printed . i aded the slots for the nut . picture later .