Seven Tips for 3D Printing with Nylon 12CF

If you’ve been thinking of trying out Nylon 12 Carbon Fiber (12CF)  to replace aluminum tooling or create strong end-use parts, do it! All the parts we’ve built here at PADT have shown themselves to be extremely strong and durable and we think you should consider evaluating this material.

Nylon 12CF filament consists of black Nylon 12 filled with chopped carbon fibers; it currently runs on the Stratasys Fortus 380cf, Fortus 450 and Fortus 900 FDM systems when set up with the corresponding head/tip configuration. (The chopped fiber behavior requires a hardened extruder and the chamber runs at a higher temperature.) We’ve run it on our Fortus 450 and found with a little preparation you get excellent first-part-right results.

Forming tool printed in Nylon 12CF on a Stratasys Fortus 450 FDM printer. Build orientation was chosen to have the tool on its side while printing, producing a smooth curved surface (the critical area). (Image courtesy PADT)

With Nylon 12CF, fiber alignment is in the direction of extrusion, producing ultimate tensile strength of 10,960 psi (XZ orientation) and 4,990 psi (ZX orientation), with tensile modulus of 1,100 ksi (XZ) and 330 ksi (ZX). By optimizing your pre-processing and build approach, you can create parts that take advantage of these anisotropic properties and display behavior similar to that of composite laminates.

Best Practices for Successful Part Production

Follow these steps to produce best-practice Nylon 12CF parts:

  1. Part set-up in Insight or GrabCAD Print software:
    • If the part has curves that need a smooth surface, such as for use as a bending tool, orient it so the surface in question builds vertically. Also, set up the orientation to avoid excess stresses in the z-direction.
    • The Normal default build-mode selection works for most parts unless there are walls thinner than 0.2 inches/0.508 mm; for these, choose Thin Wall Mode, which reduces the build-chamber temperature, avoiding any localized overheating/melting issues. Keep the default raster and contour widths at 0.2 inches/0.508 mm.
    • For thin, flat parts (fewer than 10 layers), zoom in and count the number of layers in the toolpath. If there is an even number of layers, create a Custom Group that lets you define the raster orientation of the middle two layers to be the same – then let the rest of the layers alternate by 90 degrees as usual. This helps prevent curl in thin parts.
    • Set Seam Control to Align or Align to nearest, and avoid setting seams on edges of thin parts; this yields better surface quality.

2. In the Support Parameters box, the default is “Use Model Material where Possible” – keep it. Building both the part and most of the surrounding supports from the same material reduces the impact of mismatched thermal coefficient of expansion between the model and support materials. It also shortens the time that the model extruder is inactive, avoiding the chance for depositing unwanted, excess model material. Be sure that “Insert Perforation Layers” is checked and set that number to 2, unless you are using Box-style supports – then select 3. This improves support removal in nearly enclosed cavities.

3. Set up part placement in Control Center or GrabCAD Print software: you want to ensure good airflow in the build chamber. Place single parts near the center of the build-plate; for a mixed-size part group, place the tallest part in the center with the shorter ones concentrically around it.

4. Be sure to include a Sacrificial Tower. This is always the first part built, layer by layer, and should be located in the right-front corner. Keep the setting of Full Height so that it continues building to the height of the tallest part. You’ll see the Tower looks very stringy! That means it is doing its job – it takes the brunt of stray strings and material that may not be at perfect temperature at the beginning of each layer’s placement.

Part set-up of a thin, flat Nylon 12CF part in GrabCAD print, with Sacrificial Tower in its correct position at lower right, to provide a clean start to each build-layer. (Image courtesy PADT)

5. Run a tip-offset calibration, or two, or three, on your printer. This is really important, particularly for the support material, to ensure the deposited “bead” is flat, not rounded or asymmetric. Proper bead-profile ensures good adhesion between model and support layers.

6. After printing, allow the part to cool down in the build chamber. When the part(s) and sheet are left in the printer for at least 30 minutes, everything cools down slowly together, minimizing the possibility of curling. We have found that for large, flat parts, putting a 0.75-inch thick aluminum plate on top of the part while it is still in the chamber, and then keeping the part and plate “sandwiched” together after taking it out of the chamber to completely cool really keeps things flat.

7. If you have trouble getting the part off the build sheet: Removing the part while it is still slightly warm makes it easier to get off; if your part built overnight and then cooled before you got to it, you can put it in a low temp oven (about 170F) for ten (10) to 20 minutes – it will be easier to separate. Also, if the part appears to have warped that will go away after the soluble supports have been removed.

Be sure to keep Nylon 12CF canisters in a sealed bag when not in use as the material, like any nylon, will absorb atmospheric moisture over time.

Many of these tips are further detailed in a “Best Practices for FDM Nylon 12CF” document from Stratasys; ask PADT for a copy of it, as well as for a sample or benchmark part. Nylon 12 CF offers a fast approach to producing durable, custom components. Discover what Nylon 12CF can mean for your product development and production groups.

PADT Inc. is a globally recognized provider of Numerical Simulation, Product Development and 3D Printing products and services. For more information on Nylon 12CF and Stratasys products, contact us at info@padtinc.com.

Thoughts from my day in a smart home – the importance of connecting right

When I was asked to take part in a demonstration put on by one of our local communication companies, Cox Communications, showing off what a “smart home” looks like, I of course said yes.  I love gadgets, and smart gadgets more.  On top of that it was another chance to evangelise on the power of 3D Printing.  And I got to hang out in a brand new luxury condo in Downtown Phoenix, a post kid lifestyle change that is very appealing.  Plus we deal with customers designing and improving Internet of Things (IoT) devices all the time, and this is the perfect chance to see such products in action.

So I packed up one of our Makerbots, none of our Fortus machines fits in the back of my Prius, and headed downtown.  The first thing that shocked me was that I had the printer, my iPhone, iPad, and laptop connected to their network in about one minute.  The printer showed up on the Makerbot Print app on my iPad and I was printing a part in about three minutes.

My station, showing off 3D Printing in the home.

The whole point of the demonstration was to show how the new high-speed Internet offering from Cox, Gigablast, can enable a true smart home.  So I was focused on the speed of the connection to the Internet, which was fast.  What I didn’t get till I connected was that the speed and bandwidth of the WiFi in the house was even more important.

When everything was connected, we had 55 devices on the local network talking to each other and the Internet. At one point I was downloading a large STL file to the printer while on a teleconference on my iPhone and my “roommate” was giving a violin lesson to one of his students in Canada.

Oh, and the roomba started to vacuum the floor. On the balcony someone was giving a golf lesson and a doctor was diagnosing a patient in the master bedroom.  That was on top of the smart kitchen gadgets.  And it all worked.  Yes, it all worked.

I’m trying to convey shock and surprise because the reality is that nine times out of ten when I show up for some event, at a customer, or at a friends house and we try and connect things to the internet… it doesn’t work.  If you are a technical guy you know that feeling when your vacation or visit for dinner turns into an IT house call.  All I could think of was how awesome it was that everything worked and it was fast.

So I went to work printing little plastic Arizona style houses with COX on the roof. And then a reporter showed up. “3D Printing, interesting.  Hmmmm…  they are cool and all but really, what does that have to do with a smart house?”  Damn reporters and their questions.  I was still reveling in the fact that everything worked so well, I hadn’t taken to time to think about the “so what.”

Then I thought about it.  3D Printing in the home is just now starting to take off, and the reason why is actually high-speed internet connections. If you wanted a 3D Printer in your home in the past you needed the printer, a high end computer, and some good 3D modeling software on that computer.  Basically you had to create whatever you wanted to make.  Unless you are a trained engineer, that may not be so easy.

My “house” that I was printing at the invent sits on the cloud in my Thingiverse account.

But with a well connected home you have access to places like Thingiverse and Grabcad to download stuff you want to print.  And if you do want to create your own, you can go to Tinkercad or Onshape and use a free online 3D modeler to create your geometry.  All over the web, even on a pad, phone (I don’t recommend trying to do modeling on a phone, but it does work), or on a basic computer.  The files are stored in the cloud and downloaded directly to your printer.  No muss, no fuss.  All you need is a reliable and fast connection to the internet and in your home.

High speed internet and a smart 3D printer makes anyone a maker.

And when we had a three hour break, I went downstairs to a coffee shop on the ground floor of the condo and worked, while monitoring my builds using the camera in the smart 3D Printer.

Pretty cool when you step back and think about how far we have come from that first Stereolithography machine that PADT bought in 1994.  We had to use floppy disks to get the data from our high-end Unix workstation to the machine.  Now it sits on the web and can be monitored.

This may be what we have been waiting for when it comes to 3D Printers in the home moving beyond that technologists and makers.

I’ve been focused on my experience with the 3D printing in the smart home, but there was a lot more to look at.  Check out these stories to learn more:

Phoenix Business Journal: Cox shows off a smart home with 55 connected devices and fast gigabyte internet

The Arizona Republic: Cox ‘smart home’ in Phoenix displays future at the push of a button

I also did a piece for the Phoenix Business Journal while I was at the event on “3 keys to success for smart home devices” based on what I learned while playing with the other devices in the smart home.

All and all a good day.  Oh, and being a 10 minute walk from my favorite pub made the idea of living downtown not such a bad idea, which doesn’t have much to do with high speed internet, connected devices, or 3D Printing.  But one of my goals was to check out post-child urban living…