Reducing Stringing with TPU95

[Kathryn 0]

I've recently started printing a set of stoppers out of Ultimaker's TPU95 material. This material is great and extremely shock absorbent, but it tends to string more than other filaments due to its flexibility. This becomes a slight issue when printing two of these stoppers in the same build tray, since when it goes from one tower to another it will string and leave a small blob of material on the surface of the part. In other materials these blots can be easily taken off, but with TPU it becomes harder since the material tends to elastically stick together. Has anyone found any particularly good retraction settings to reduce stringing in TPU?

 

Here's a picture to illustrate the blotting I'm talking about, seen on the front surface of the square tower:

 

[Brulti 177]

I solved the problem by printing pieces one at a time when it comes to TPU95A. It won't take more time anyway, you'll just have two 1h print instead of one 2h print. ?

[Kathryn 0]

That is certainly a possible approach - the problem is that this Ultimaker is being set up to be used in production, which means it would be expected to make trays of parts at a time to reduce change-over/excess handling. If it were just for engineering though I agree, printing one at a time would work fine.

[Brulti 177]

Based on personal experience, I would strongly advise against the printing of trays of parts for one simple reason: if something goes wrong and a print fails, it's better to loose one part and one hour of printing, plus the material used for that part, than 10 parts and ten hours of printing, plus the material used for said parts.

 

As for change over and excessive handling, you just need to buy a second glass bed: when the first print is done, you remove the glass bed, put in the second one and start the print of the second part, which takes about one minute or two. Then you can get the first print of the first glass bed, clean the glass and you're ready for the third print.

[orangesale 2]

I currently have the same problem as I need to print about 360 plugs, printing them one at the time wont be a solution.