What are the best locking methods for plastic parts?
What are the best locking methods for plastic parts?
(OP)
Hello Everyone,
Hope All is well...
I'm working on a concept...I have attached my rough sketch (sorry, bad sketches). It has two parts PART -1(Base) and PART-2(Top). Part-2 will slide into the hollow section of part-1 and part-2 need to hold at three different heights (indicated as stage 1 to 3 in my sketch) to carry some load. I was stuck in selecting the locking method for holding the part -2 at required height. Initially, I thought to put some pins through the holes (from all sides) to hold part-2 but I'm thinking for a different and easy way to hold/lock the part-2 at required height. These are 3D printing parts (ABS Plastic).
Any thoughts/suggestions?
Any kind of help is appreciated...
Thank you..
Hope All is well...
I'm working on a concept...I have attached my rough sketch (sorry, bad sketches). It has two parts PART -1(Base) and PART-2(Top). Part-2 will slide into the hollow section of part-1 and part-2 need to hold at three different heights (indicated as stage 1 to 3 in my sketch) to carry some load. I was stuck in selecting the locking method for holding the part -2 at required height. Initially, I thought to put some pins through the holes (from all sides) to hold part-2 but I'm thinking for a different and easy way to hold/lock the part-2 at required height. These are 3D printing parts (ABS Plastic).
Any thoughts/suggestions?
Any kind of help is appreciated...
Thank you..
Thanks & Regards,
Sam





RE: What are the best locking methods for plastic parts?
Read up on snap fits to get started. In this case, you probably want conical bumps, because you need to slide them into and out of engagement during your staged assembly process.
They don't have to be circular; they could be obround.
Keep them away from the corners, where the walls will be extra stiff.
Mike Halloran
Pembroke Pines, FL, USA
RE: What are the best locking methods for plastic parts?
Mike Halloran
Pembroke Pines, FL, USA
RE: What are the best locking methods for plastic parts?
Thanks & Regards,
Sam
RE: What are the best locking methods for plastic parts?
Mike Halloran
Pembroke Pines, FL, USA
RE: What are the best locking methods for plastic parts?
Thanks & Regards,
Sam
RE: What are the best locking methods for plastic parts?
Thank you for your suggestion on snap fits. Will snap fit work good on a frequent changes? Also, these parts will be 3D printed. Is there any specific type of snap fit that works for my application? Please advise...
Thanks & Regards,
Sam
RE: What are the best locking methods for plastic parts?
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm
RE: What are the best locking methods for plastic parts?
Thanks & Regards,
Sam
RE: What are the best locking methods for plastic parts?
another day in paradise, or is paradise one day closer ?
RE: What are the best locking methods for plastic parts?
Without any sizes, dimensions, wall thicknesses, loads, etc. it is pretty difficult to know what to do. With plastic parts, the through holes and pins are somewhat suspect becuase all of the supported loads and manufacturing activity going on above are supported on a couple pins, at four bearing holes, but maybe only two bearing points until some yielding has taken place. The holes will elongate due to the bearing stresses and due to the repeated insertion of the pins. Finally, imagine the farting around of putting the pins into (through) the four holes each time you want to change heights. Also, how is part-2 lifted or lowered from one stage to the other? Can the worked do this by hand, or is it done mechanically, in some way? Finally, you talk mostly only about stages 1 and 2, but you show holes for 3 stages; and in fact there could be a 4th stage with the lower end of part-2 resting on the top of the base plate of part-1, so which is it? For the life of me, I don’t understand how you OP’ers. think you will get better discussion if you give the problem very little forethought, and then you give none of the pertinent design info. We don’t know if parts-1 & 2 are about 1" and 1.5" tubes or if you can get a couple people inside of part-2, and that could make a difference in a good, practical solution.
To get at least three stages of adjustment, I would start out with the bottom end of part-2 resting on the base plate of part-1. Inside part-2, I would have a set of two 1" high bearing blocks on the x-axis (one at +x and one at -x), almost as wide as the inside dim. of part-2. When these blocks are pushed outward against part-1 inner walls, and part-2 is lowered onto them, you are at your stage-1. Similarly, on the y-axis, but 2" high bearing blocks, with width smaller than above by double the thickness of 1" blocks, for clearance. Pushing these y-axis blocks to the inner walls of part-1, gets you to your stage-2. Now, one of the questions again, can we get people in there to set the bearing blocks or do we need a 1" long cylinder or mech. actuator? There may be some significant advantage to having part-2 be the larger tube, slipping over part-1. Now this bearing blocking can be accomplished from the outside, with different ht. blocks acting only on one axis, and just use 2" bearing blocks instead of 1" blocks at same holding device.
RE: What are the best locking methods for plastic parts?
RE: What are the best locking methods for plastic parts?
So, they could be concentric cylinders, then. In that case, you could have pegs on the inner cylinder that ride a milled out channel on the outer cylinder that has detents for the levels you want to stop at.
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm