Precise prints. Making loose fitting pieces fit more tightly. (White Strong Flexible)

Hi All,

I have had my first print come back, which were some game pieces which have lids. I had two sets, one in White-Strong-Flexible and one in Black-Strong-Flexible. They printed really well. I knew before ordering that there may be an issue with the tightness of the lids since the exact millimetre printing can't be guaranteed, and the pieces are only about 2cm wide. I didn't get them smoothed by shapeways. As it happened;

The Black set are all fairly tight fitting, and some needed to be 'worn in', to get them looser which is fine.

The White set are opposite, most fittiing as desired but a few are too loose. The reason it's important is you need to be able to move the pieces by lifting them by the lids without the bottoms falling down, as removing the lids is a game element.



So my question is regarding my white pieces. The lids have a 1mm or less gap where they grip the pieces, so I don't need to do much to make them tight.


What advice do people have for modifying White Strong flexible to make the lids more tight.

Ideas I had were:

a) Scratching inside the lids to make them rougher. But since the lid walls are quite thin, I didn't want to risk damage by doing this as my first try. Also the new roughness may also wear down with use anyway.

b) Add some superglue to the inside of the lids, letting it dry completely so adding extra matterial. I guess that superglue will not dissolve White Strong flexible?

What I did first was to add some thin strips of sellotape (weak sticky-tape) inside the lids where they grip the pieces. It works, but over time the bits of tape come off, and as they get used I expect more pieces to start getting loose as they get smoothed so would like a better fix.

Anyone else done any precise prints and noticed a mm size difference from White and Black Strong flexible?
Black pieces seem to be more rough than White, and White came from the Printer with more power on them. Is there is some difference between the two matterials when it comes to precise prints?.. or maybe it is just my particular prints that happened to come out slightly differently.

Any other comments/recommendations about making pieces which 'click' together, or precise printing? The only way I think I could modify the design to make a difference to this issue is by increasing the facets/poly on the pieces which are round, 34poly. I left them as 34 facets for aesthetics and thought it might aid the griping. I could reduce the gap to zero, but since the Black pieces came out ok, I am not sure what to try.

Generally very pleased with how the pieces came back as they are prototypes. If I choose to sell the pieces in the shop, I need to either make people aware and find a reasonable solution or find a fix at the print stage.

Thanks.
3dinLeiden

I can't really help much as I haven't really compared materials.

That said, I have been printing articulated action figures which rely heavily on accurate prints for the joints to work properly and found that zero tolerance for fitting pieces never quite worked. It seems the negative part/spaces of the joints always come out slightly smaller/collapsed so I've had to go in and carve them out a little here and there. Still trying to model the joints slightly loose and see if that gives me something that fits properly and is still tight.
So far tho, I've ordered about 5-6 test prints and the accuracy issues seem to be pretty consistent for me, using always the same material.

For durability, I coat all the joint areas with testors liquid cement. The glue that isn't absorbed by WSF evaporates completely and the glue that does get absorbed seems to strengthen the area, feels more sturdy and resistant. You can maybe try that if you're worried about things wearing out too much.

Also, if you're painting your WSF pieces, areas coated with the liquid cement may not absorb the paint anymore very well, it will be more like painting on regular plastics at times.


good luck.

I would refer to Material comparision chart

https://www.shapeways.com/materials/material-options/?li=faq

There is minimum detail parameter that can help you to understand when separation of pieces occur and then you can add additional to make it more lose.

Game designer here. The issue I see with your solutions is that they still seem mostly temporary - the grippyness is _going_ to wear out eventually and frustrate your players.

I don't know your game mechanics, but I would consider altering the premise that they should be able to lift the piece by the lid. This is what is causing most of your problems. Personally, I would try to make it harder for them to lift by the lid at all, and make it easier to lift the piece by the body. For example see the attached images:



If you absolutely need it to be liftable by the lid, then you may want to look into doing a threaded cap (and I don't know how well this would work), -or- using some kind of simply hook locking mechanism where the cap has protrusions pointing inward and the body has segments cut out (similar to how childproof bottles work, but not quite as elaborate).

--Rhalin

Well, I don't see anything mentioning the size of these containers (other than that ambiguous "2cm wide") but I'd suggest simplifying it even more... instead of threads (which can be a pain to create...) use "lugs" or flanges - just a quarter turn or less, and it comes off, but it doesn't have to be real tight, and you can lift by the lid. A loose fit wouldn't be so much of an issue with this kind of design...

This is WAY overkill, but it should make it a little more clear what I'm talking about...




But you DO realize that lids in separate pieces that are critical to the game play are going to be the FIRST pieces to get lost, right?