Thumb loop for post style cams

I purchased and put one of these onto my #2 OP link cam about a year ago. Fit was great and did make it less clumsy to handle, but the sling would slip between the 2 plastic pieces when weighted in a direction other than mostly straight down the direction of stem. I did not like the sling between the two plastic pieces, but did not think it would cut. I would use firm silicone instead of plastic next time.

Additionally, I did not find that the loop was durable. After about a month or so I found the plastic broken in my pack. I think it happened when I stuffed my rack into the pack indiscriminately as one would normally do. 

Conclusion: Good idea. It works, but iteration #2 I would use a different material, maybe silicone or something that won't fracture. Did not find the original material to be durable. 

Seton Kriese wrote:

Probably a non-issue. Because 3d prints are essentially a series of layers of extruded plastic beads (if that makes any sense) they tend to leave rounded edges when they break (following the line of weakness). I haven't seen any break leaving sharp edges. Anyone else?

Depends on the type of additive manufacturing. You are talking about an FDM process, which the OP shows as well. But from shapeways you can buy parts in a variety of mfg processes. Ive seen high precision fdm machines print parts that when broken can leave sharp edges. same thing with SLS, DMLS, SLA, etc.

That being said, I think this is a wonderful idea. OP, you should run that design through an FEA and see what type of stress/strain and deformation you get. (appoligies if you have done this, i didnt read the whole thread, or OP since it was posted) Typically my first designs suck and I end up iterating to a better design that ultimately wont break in real life scenarios. 

im an ME fwiw. you can pm me if you want to get into more specifics too. 

Cheers

OK GUYS, ELASTOMERIC FDM PRINTING.  

MEANING THE PART IS SQUISHY!!!! 

AKA RUBBER LIKE. REPLACE SCREWS WITH A ZIPPY TIE.

 DONE. NO SHARP EDGES.

Cortney LeNeave wrote:

Depends on the type of additive manufacturing. You are talking about an FDM process, which the OP shows as well. But from shapeways you can buy parts in a variety of mfg processes. Ive seen high precision fdm machines print parts that when broken can leave sharp edges. same thing with SLS, DMLS, SLA, etc.

That being said, I think this is a wonderful idea. OP, you should run that design through an FEA and see what type of stress/strain and deformation you get. (appoligies if you have done this, i didnt read the whole thread, or OP since it was posted) Typically my first designs suck and I end up iterating to a better design that ultimately wont break in real life scenarios. 

im an ME fwiw. you can pm me if you want to get into more specifics too. 

Cheers

Yes, FDM was what I meant. I didn't know other methods were prevalent online yet. I'm an engineering student in canuck land so I'm starting to learn some FEA stuff (not in class yet, but by trial and error on club projects). I agree that this definitely one of the most interesting MP threads.

Have a nice day

just curious if there was any upgrades or improvements since this thread dropped off

Seton Kriese wrote:

Probably a non-issue. Because 3d prints are essentially a series of layers of extruded plastic beads (if that makes any sense) they tend to leave rounded edges when they break (following the line of weakness). I haven't seen any break leaving sharp edges. Anyone else?

This actually IS an issue. FDM printers do leave shard edges from portions of the printing process (especially rafts and brims). They are extruded filament, not beads, and after melting and being extruded can leave very sharp edges, razor blade sharp in some cases. They are just plastic after all and will exhibit properties of plastics, including sharp edges and shards on failure. However, if done in elasticized material, no problems.

For durability and flexibility, try printing with nylon.  Stuff is super tough and is not brittle/prone to shatter or crack.

Pete Spri wrote: For durability and flexibility, try printing with nylon.  Stuff is super tough and is not brittle/prone to shatter or crack.

You are right that nylon likely won't crack in use, but I would still warn to be careful of sharp bits from the printing process and make sure they are smoothed out before use.