Flexvat V5, the best of both worlds.
Posted: Sat Feb 18, 2017 11:03 am
I have been getting requests for a vat that supports the FEP film release layer on a sheet of transparent acrylic. I have resisted designing a vat with an acrylic window for a couple of reasons first of which is the inferior release characteristics of a vat that uses FEP film sitting on a support. When FEP film is sitting on a transparent window it does not easily flex upwards when the build plate rises during the peel stage of a layer exposure because of it being stuck to the support plate due to vacuum and other issues. A big reason that drumkead flexvats work so well is the fact that when the build plate rises the FEP film can bulge slightly upwards and peeling edges tend to develop at any edge that is touching the FEP film so peeling starts pretty much anywhere it needs to, this is not the case for FEP film sitting on a support, on a support FEP film acts as a rigid "plate" rather than a flexible "drum". The bottom line is that drumhead flexvats when properly tensioned work and vats with supported FEP film work less well and I was not willing to put a vat into the wild that worked less well.
The people who asked for a vat design using supported FEP film do however have valid reasons for wanting such a vat. At the top of the list seems to be user friendliness, a vat with supported fep film doesn't require tension adjustments, also, the film is more resistant to puncture due to catastrophic build failure ("hey joe the stiletto build just went south"). A lower focal plane is also often mentioned.
I think I have a design that will both satisfy the need for a "supported" vat and a "drumhead" vat in a single package that has the advantages of having both a lower focal plane and fewer parts while allowing vat users to switch between the two vat types. The new vat uses transparent acrylic inserts (drumhead and supported) that are held against the FEP film under tension by a snap in retainer. The snap in retainer allows you to change the vat type when needed (if you need the lowest possible release forces use the drum insert, if the release force is not so critical use the support insert)
I will finish my testing on the vat next week, if everything pans out the vat should be available in a week or two over at flexvat.com.
HTL
The people who asked for a vat design using supported FEP film do however have valid reasons for wanting such a vat. At the top of the list seems to be user friendliness, a vat with supported fep film doesn't require tension adjustments, also, the film is more resistant to puncture due to catastrophic build failure ("hey joe the stiletto build just went south"). A lower focal plane is also often mentioned.
I think I have a design that will both satisfy the need for a "supported" vat and a "drumhead" vat in a single package that has the advantages of having both a lower focal plane and fewer parts while allowing vat users to switch between the two vat types. The new vat uses transparent acrylic inserts (drumhead and supported) that are held against the FEP film under tension by a snap in retainer. The snap in retainer allows you to change the vat type when needed (if you need the lowest possible release forces use the drum insert, if the release force is not so critical use the support insert)
I will finish my testing on the vat next week, if everything pans out the vat should be available in a week or two over at flexvat.com.
HTL