alright , just gotta keep manufacturability in mind. Dont want to design something and have it be impossible or really really expensive to make
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theres a chance those are cast.
No I’m 100% positive machined.
The reason why the gland needs to be on the body is to account for tilt of the piston. In order for maximum extension you want maximum overlap of the oring, which means the oring needs to be either near the outer surface of the body, or the inner edge of the piston. If the oring is on the inner edge of the piston, then any side force will cantilever the piston against the lip and cause excessive side motion on the oring surface, causing possible leak and excessive wear. Not to mention dirt will get in between the body and piston. The solution is to put the oring near the lip of the body, sealing out dust and also at the location where cantilevering of the piston will have minimal effects on side motion of the o-ring.
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Look up videos of internal groove milling if you’re curious. Can be done both by CNC or lathe.
I specifically thought of this part with simplicity of production in mind. 4 round objects in total with 3 sealing surfaces for the entire system. Anyone with a lathe can make this part with relatively basic tooling. If you want to go CNC route with bigger MOQ, then they might have to look in a tooling catalog for the internal groove, just depends on how many you want to make.
Got it. I’ll take that into account.
Do t hold your breath on this. I’ve got midterms next week, but after that is spring break. There seems to be enough communityinterest here that I’ll keep working on it. As opposed to a certain flash light design…
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If you’re actually thinking about making it, I can help you more in depth with the design on tolerances and seal selections etc. I did have a background in aerospace CNC and I’m pretty good at simplifying design constraints for ease of production.
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That sounds like a very useful resource, thank you.
I do think its worth at least building a prototype.
I cant promise you that I will have the time to follow through on everything.
God knows I’ve dropped a few projects after biting off more than I can chew.
Maybe this time is different.
Excuses Excuses
Id like to point out in my defense of past projects, I work 40 hours and doing full time masters in EE.
I don’t sleep really
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…dammit
I just thought of an addition to this, a spring in line with the linear actuator can be used to increase force in one direction. Since we only need compression forces, lets say we have a 100N actuator, it is likely it can do 80-100N in reverse as well, which means we can put, say, a 50N spring and have 150N push and 30N retract, etc.
Alternatively could use a gas piston in pull compression for ramping of pressure opposing the pressure increase from bushings.
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The reason to do this would be if we can’t make the force redistribution work out? Seems like a particular piece of spring to source
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Sourcing springs in various strengths is fairly easy. Lot of off the shelf solutions. It just occured to me it can be used to take some stress off the actuator and increase speed/longitivity
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“The difference between Science and [Fucking] around, is writing it down” - Adam Savage
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