Yes, You Can Print TPU On A CR-10s With No Mods (Part 2)

In my previous post, I showed that it was indeed possible to print TPU on a plain old CR-10s. That was with a couple of sample packs that had no name on them but had the following recommendations:

• Nozzle: 220-240C
• Bed: 75-85C

With that sample TPU, I had success printing at around 20mm/s with a nozzle temperature of 240C and a bed temperature of 75C.

I ordered the a spool of the cheapest black TPU I could find on Amazon, sold by a company named Priline. The recommendations for this TPU were different than the other stuff I’d used:

• Nozzle: 190-230C
• Bed: 50-80C

I thought I’d print the same nut and bolt models that I’d done before to compare. I made the temperature changes in Cura, then sent it off to print, first with a nozzle temperature of 220C and a bed temperature of 75C.

Right off the bat I could see there was a problem. The lines weren’t adhering to each other as they were being printed. I tried bumping up the flow rate, which only made things lumpier. Then I turned up the temperature a few degrees at a time until it looked like things were working better. Unfortunately, the print failed on the second layer when it didn’t stick to the first layer and became a blob on the nozzle.

I ran another print with the temperature set to 230C and with the flow rate still higher. The first layer went down a lot better and I thought things were going to work but the fourth layer didn’t stick to the third and it ended up all over the nozzle again. I thought that might’ve been a fluke, so I leveled the bed again and tried again but had the same results on the sixth layer.

Another print started at 235C and was working pretty well but once there were about a dozen layers put down, it didn’t look right. I cancelled the print, let everything cool down, and then took a look at the parts. With a bit of pulling, I was able to separate some of the layers. Still no good.

Despite the recommendations being only up to 230C, I tried bumping it up one more time to 240C, just like the TPU from the sample packs. That extra five degrees made a world of difference. There was some over-extrusion so I turned the flow rate back down a bit.

Here’s what I ended up with. You can see there’s a bit of stringing between the models just like last time:

Here are two comparison pictures of the nut and bolt printed with the sample TPU on the left, and the Priline TPU on the right:

Both had some stringing, but it’s pretty obvious that the Priline printed cleaner than the sample packs did. From the look of it, I probably should’ve dried the sample TPU before I used it.

After the print, I compared my notes and found that the settings that had finally worked for the Priline were exactly the same as I’d used when printing with the sample filament:

• Speed: 19mm/s
• Nozzle temperature: 240C
• Bed temperature: 75C
• Flow rate: 105%
• Retraction: OFF

These results make me even more confident in saying that yes, a stock CR-10s can print TPU and do a decent job at it.