FAQ- Fluorinar™ Kynar® Filament

Fluorinar™ Kynar® PVDF Filament
What printer and slicer do you recommend for your Fluorinar™ PVDF filaments?

The main requirement for a successful print is a heated build plate. The printer you select must be able to maintain a heated glass build plate at 100C. We have tried many printers and so have our customers. Collectively we have converged on the Ultimaker models. These are not priced as an entry-level machine, but a generally considered an industrial/prosumer choice. We have found the Ultimaker machines provide very consistent results with almost zero downtime. Ultimaker also provides the Cura slicer software at no additional cost. This slicer is continually updated and improves with every release. Ultimaker machines and the Cura software make a combination that is hard to beat.

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 PVDF legacy.

The Fluorinar-C™ material is made from a Kynar® PVDF copolymer. It is polymerized with the VDF monomer and hexafluoropropylene (HFP) monomer. 100% HFP is a fluoroelastomer known by the old DuPont tradename Viton®. Fluorinar-C™ has increased flexibility, slightly lower crystallinity and melting temperatures and slightly different chemical resistance. The most important advantage of this filament is increased build plate adhesion which results in better prints.

The Fluorinar-B™ is our PVDF copolymer with additional pigmentation. The pigment helps minimize the surface stress against the build plate. 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 that 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. While also made from a PVDF copolymer, the presence of the graphene results in loss of build-plate adhesion. So attention to part design, use of brims and adhesive are important factors to consider for a successful print.

Botton line is that all four filaments address very specific needs. However, if you are new to PVDF printing 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. Apply a single continuous layer of Elmer’s disappearing purple glue on the glass build plate 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 often not required for Fluorinar-B™
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 depending on part geometry.  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 100% in order to get the rod holder and smokestack features nice and round. A detailed list of print parameters for 3DBenchy is available on this page.

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 to the 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. Exposure of your PVDF print to acetone will cause the interlayers to disbond. Limonene has a boiling temperature around the softening point of the Fluorinar filaments, 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. It 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 readily 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 will my Fluorinar™ print hold up in a specific chemical application?

The effects of chemical exposure to our Fluorinar™ materials is extremely important. We provide a table of the chemical resistance of our Fluorinar™ filaments here. However, reality can be much more difficult with variations in temperature, concentrations and varieties of chemicals often present. To help your material evaluation, we recommend that you print some tensile-test samples and expose them to your specific environment. An STL print file for this sample is found at the Thingiverse web site. Once samples have been printed, they can be weighed and placed into your environment. You can drill a small hole in the end of the dog bone and tie a PTFE line used for tooth floss onto the sample. After 1, 2 or 4 weeks these samples can be removed and weighed again. Lack of significant weight gain is often a good indicator of material compatibility to your application.

We also prove some general guidance on the chemical compatibility of our filament.

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.