"Easiest" soft/flexiable material

[gardnert 1]

Good morning everyone!

I work/teach with a UM3 at my job, and an assignment I've worked on in the past are hanko: Japanese stamps. (these are for a Japanese culture class)

We've used TPU as the business end of the stamp (combined with a PLA body), but to be "culturally accurate" the heads of these stamps are pretty narrow in diameter, and the TPU gets pretty oozy -- losing a lot of details the students really wanted to keep. You can see in the attached image, the center stamp works well, but the one on the right is suffering.

 

 

My question is: can anyone suggest a good material for a stamp face? PLA and harder plastics don't handle the ink well.

[geert_2 432]

I have no experience with soft 3D-printing materials. But soft plastics do not necessarily handle ink better. There are lots of soft plastics that do repell water, like PP and PE, so they wouldn't work at all.

 

Have you tried treating the surface of PLA-stamps, to accept the ink better? Or try changing the ink, so it adheres better? If you could print in PLA, you would get the best details, I think.

 

For example, try lightly sanding the stamp surface with fine gritt paper, so it is matte? And try adding a little bit of alcohol to the ink, so it spreads easier onto the stamp?

 

The advantage of sanding (or similar treatment) of the print-surface only, would be that the symbol attracts the ink well, while the rest of the stamp repells it. This might give more accurately printed/stamped symbols on paper?

 

[gardnert 1]

5 hours ago, geert_2 said:

I have no experience with soft 3D-printing materials. But soft plastics do not necessarily handle ink better. There are lots of soft plastics that do repell water, like PP and PE, so they wouldn't work at all.

 

Have you tried treating the surface of PLA-stamps, to accept the ink better? Or try changing the ink, so it adheres better? If you could print in PLA, you would get the best details, I think.

 

For example, try lightly sanding the stamp surface with fine gritt paper, so it is matte? And try adding a little bit of alcohol to the ink, so it spreads easier onto the stamp?

 

Thanks for the interest and reply!

I will definitely give the sanding a try. One of the main reasons I was using TPU was it has a certain aesthetic when being used as a stamp: the PLA would offer the same feel if we were say wax sealing an envelop or letter. But I think i'm willing to give that up for the students to have the detail they're looking for.

[AndersK 41]

You could also do a combination of the materials.

 

First print the base with TPU then a fairly thin top shell of PLA. You'll get the flexibility and great details.

To have them bond well I would model "anchors" in the PLA part. (Assuming you have dual extruders)