aarongough
Stainless
- Joined
- Oct 27, 2014
- Location
- Toronto, Canada
Hey all!
I have come across a real head-scratcher of a problem. What I'm trying to do is to make a CAD model that is the same as a part that I normally thermoform from Kydex. The hot kydex is laid across this mold:
And then pressed down onto the mold using high density foam in a pneumatic press. This produces parts that are not an exact match to the mold. Instead because of the relatively thick kydex (0.080" thickness) they have 'drape' where the hard inside corners of the mold are transformed into flowing curves on the part. You can see what the resulting parts look like here:
After forming the sheet is CNC trimmed as you can see above.
The two halves are then attached together with rivets, which produces the sheath you see on the left here:
The resulting sheath uses elastic deformation of the kydex material to hold the knife in place without the need for straps or clips. When you push the knife in the 'lips' of the sheath are pushed outward, then snap back inward, into the finger groove in the knife handle, to hold the knife in place.
I am trying to re-design this part so it could potentially be 3D printed, and it has turned out that re-creating that 'snap fit' (for lack of a better term) has been extremely challenging. I have made some models that work, but tuning the strength of the fit is very challenging and the shape that I was able to make in CAD does not operate as smoothly as the thermoformed version...
Here are some photos of the printed versions I have made so far:
In addition to 3D printing I am also considering making a 'hard tool' from steel which would trim/form a sheet of hot kydex in a single stroke.
So my question is: how can I replicate the 'drape' of the physical thermoforming process in CAD? Surely there must be a tool out there that allows you to plastically deform one solid over another?
I know blender has some tools that 'kind of' do this, but they don't look like they're configurable enough to produce the result I need... I'm curious if anyone knows of other tools that will do this?
I'm honestly at the point where 3D scanning is starting to look like the right solution, but that seems a bit nuts!
-Aaron
I have come across a real head-scratcher of a problem. What I'm trying to do is to make a CAD model that is the same as a part that I normally thermoform from Kydex. The hot kydex is laid across this mold:
And then pressed down onto the mold using high density foam in a pneumatic press. This produces parts that are not an exact match to the mold. Instead because of the relatively thick kydex (0.080" thickness) they have 'drape' where the hard inside corners of the mold are transformed into flowing curves on the part. You can see what the resulting parts look like here:
After forming the sheet is CNC trimmed as you can see above.
The two halves are then attached together with rivets, which produces the sheath you see on the left here:
The resulting sheath uses elastic deformation of the kydex material to hold the knife in place without the need for straps or clips. When you push the knife in the 'lips' of the sheath are pushed outward, then snap back inward, into the finger groove in the knife handle, to hold the knife in place.
I am trying to re-design this part so it could potentially be 3D printed, and it has turned out that re-creating that 'snap fit' (for lack of a better term) has been extremely challenging. I have made some models that work, but tuning the strength of the fit is very challenging and the shape that I was able to make in CAD does not operate as smoothly as the thermoformed version...
Here are some photos of the printed versions I have made so far:
In addition to 3D printing I am also considering making a 'hard tool' from steel which would trim/form a sheet of hot kydex in a single stroke.
So my question is: how can I replicate the 'drape' of the physical thermoforming process in CAD? Surely there must be a tool out there that allows you to plastically deform one solid over another?
I know blender has some tools that 'kind of' do this, but they don't look like they're configurable enough to produce the result I need... I'm curious if anyone knows of other tools that will do this?
I'm honestly at the point where 3D scanning is starting to look like the right solution, but that seems a bit nuts!
-Aaron