FAQ- Fluorinar™ Kynar® Filament

Fluorinar™ Kynar® Filament
 

What diameter and color options are available in the Fluorinar™ PVDF filaments?

Fluorinar-C™ 1.75mm & 2.85 mm (white)
Fluorinar-B™ 1.75mm & 2.85 mm (black)
Fluorinar-ESD™ 1.75mm & 2.85 mm (black)
Fluorinar-H™ 1.75mm & 2.85 mm (natural)


What are the differences between the four Fluorinar™ PVDF filaments?

PVDF is commonly used throughout industry (semicon, biopharm, nuclear, chemical process) in the homopolymer form. This corresponds to our Fluorinar-H™ material. PVDF has two fluorine and two hydrogen atoms in each repeat unit. It can be thought of as the offspring of PTFE (4 fluorine atoms and PE (4 hydrogen atoms). Unlike PTFE, PVDF is fully melt-processible. The high crystallinity of PVDF makes adhesion to the build plate difficult. There is a change in the volume of semicrystalline plastics such as PVDF during the transition from the amorphous melt phase to the semicrystalline solid. This creates surface stress between the print and the build plate. This stress can be managed through careful part design (no sharp corners, fillet transitions from the bottom to the side, use of adhesive, etc.) OUr Fluorinar-H™ filament represents this 50+ year legacy.

The Fluorinar-C™ material is the PVDF copolymer. It is polymerized with the VDF monomer and hexafluoropropylene (HFP) monomer. 100% HFP is a fluoroelastomer known by the DuPont tradename Viton®. Some Fluorinar-C™ has increased flexibility, slightly lower crystallinity and melting temperatures and slightly different chemical resistance. But one advantage is increased build plate adhesion.

The Fluorinar-B™ is our PVDF copolymer with additional pigmentation. The pigment helps minimize the surface stress against the build plate. The adhesion of the printed part is so good, we rarely use extra brims during printing. It is not uncommon to break off layers of glass from the build plate during part removal if we have not allowed for sufficient cooling time.

The Fluorinar-ESD™ filament has a graphene additive which transforms the printed parts from an electron insulator to a low-end conductor which resistance equivalence of graphite. Not a great conductor but very good at static dissipation. This is an important quality in many electronic and chemical manufacturing processes.

Botton line is that all four filaments address very specific needs. However, if you are new to PVDF we would recommend either the Fluorinar-C or Fluorinar-B filaments.


What print parameters should I use for a successful print?

1. Print on a glass bed heated to 100 C.
2. Use a light layer of Elmer’s disappearing purple glue on the glass for adhesion. Other PVA adhesives have not been as effective.
3. Print with a single layer 10 – 15 mm brim attached to the part.  This is not required for Fluorinar-C™
4. Maximize part surface area in contact with the print bed.
5. Set extrusion temperature 250 – 260 C.
7. Layer height can be 0.1 – 0.2 mm.
8. Print speed should be around 20 – 40 mm/s.
9. If the part is small it will help to print in duplicate as the most recent layer on the first part is allowed to cool while the layer on the second part is printing.
10. Fluorinar-H™ likes to run hot. We never use a fan with this material.  When using Fluorinar-C™ for larger prints, a fan can be used to increase print speed up to 70 mm/s.  Keep an eye on things.  If interlayer bonding does not appear to be working then the fan or print speed can be reduced. When printing 3DBenchy with Fluorinar-C™ we run the fan up to 50% in order to get the rod holder and smokestack features nice and round.

Additional printing guidance can be found here.


How much shrinkage can I expect to see when using Fluorinar™ filaments?

To determine the amount of shrinkage in a printed part we printed examples of the 20 mm XYZ calibration cube. This STL file is available from Thingiverse.
 
Filament: Fluorinar-C™
Layer Height: 0.2 mm
Infill: 30%
X-axis = 19.80 mm (1.00%)
Y-axis = 19.87 mm (0.65%)
Z-axis = 19.65 mm (1.75%)
 
Filament: Fluorinar-B™
Layer Height: 0.2 mm
Infill: 30%
X-axis = 19.82 mm (0.90%)
Y-axis = 19.98 mm (0.10%)
Z-axis = 19.91 mm (0.45%)


What length of filament is on the spool?

Our 1 kg 1.75 mm Fluorinar™ filaments have approximately 785 feet (239 m) while our 1 kg 2.85 mm Fluorinar™ filaments have 300 feet (91 meters) on each spool.


What support materials work with the Fluorinar™ filaments?

If you can print the support directly to the build plate then HIPS or a TPU are possible candidate materials.

With HIPS, you won’t get adhesion between the support and the Fluorinar™ filament, but the HIPS will help bridge a gap between two locations. For instance, if you were printing the letter H, HIPS would help bridge the horizontal gap. If you tried to print the letter F, the two unconnected horizontal parts of the letter would not bond to the HIPS and would lift and curl. We print the HIPS at close tot he same temperature as we do the Fluorinar™ PVDF: 240C with a 100C build plate temperature, HIPS dissolves in acetone and limonene. Acetone is a slow-acting solvent for PVDF so you want to be careful with this. Limonene has a boiling temperature around the softening point of the Fluorinar, so if you use heat to accelerate the HIPS dissolving process be careful, otherwise the PVDF print will turn into a melted mess at the bottom of the beaker.

TPU is an interesting material. If you have ever purchased the foaming sealant from Home Depot, this is a form of polyurethane and it sticks to almost everything and can be a real mess. There is a slight amount of adhesion between the TPU and the PVDF, so it does make a better support material. However, there is no easy way to dissolve this so mechanical methods are the only way to remove the support. Again, we print the TPU at the same temperature at the Fluorinar™ PVDF. Also, because of the similar temperatures, there is some cross-contamination between the materials. If you are printing in our white Fluorinar-C filament with a black TPU support, you will find it difficult to remove all of the TPU and will be left with small TPU specs and inclusions. If you print with a white TPU then these inclusions are not visible.

Can you print either HIPS or TPU directly onto PVDF? Yes and no. If you have an extended brim around the part made from the support material then you print the support material directly over the print as long as the support material is in contact with the brim. For instance, if you were printing the letter B you could surround the letter with a brim made from the support material and then fill in the interior regions with support material printed directly onto the Fluorinar™ PVDF.


How soon will my order ship?

All of our Fluorinar™ filaments are off-the-shelf items that will ship within 24 hours of order placement. If we can’t meet this deadline we will contact you with a revised shipment date.