Welcome to the SeeMeCNC Community

Hey guys,


Wow im completely exhausted here and I just need some help.


Heres the deal.

The Setup

Rostock Max V2

Nylon 618 matter hackers

240C extrusion

80-90C Bed temp

Very slow printing speeds (25-30mms) for these test prints ,

but i've printed this at much faster speeds with success, just a lot of stringing has occured.


The PROBLEM

I have printed this before, with great success, its a shifter carrier bushing for BMW E30/E36. It printed extremely well over the summer time (im in upstate NY) and fit very tight, couldn't of been better.

[img]https://fbcdn-sphotos-a-a.akamaihd.net/ ... 6ef0affbc4[/img]

[img]https://fbcdn-sphotos-g-a.akamaihd.net/ ... 84de8f445d[/img]

[img]https://fbcdn-sphotos-d-a.akamaihd.net/ ... e0c7aad394[/img]


So here is whats going on now, and I have some theories on why, but wtf? Any help and advice is appreciated!!

[img]http://upload.streetlegalmods.com/image ... rbad_3.jpg[/img] [img]http://upload.streetlegalmods.com/image ... rbad_1.jpg[/img] [img]http://upload.streetlegalmods.com/image ... rbad_2.jpg[/img]

Now when im printing one (or bulk amount) the nozzle will start dragging after a few layers, the printer is calibrated, prints abs perfectly for the most part, never drags on those prints.



It seems like when the printer does infill with the nylon, it zig zags the infill in... resulting in a higher overall height on the print than the perimeters. so next layer the nozzle hits that infill...


Thats the first problem, second problem is the edges of these suckers are peeling up off the bed, wtf? how did I print the other one so well? Its winter now here and its cold , very cold, could it be the ambient room temp? it's probably 60F in here at the least, its hard to keep the temp very high in here but I have gotten it up to 70F last night but not much help... (electric heat sucks)


So, what can i do to increase the quality of these prints? What happened, in your opinion, between my successful print and this one? I know the answer is "only you would know" but really, I can't think of anything.


What you do this in this situation to start troubleshooting this issue?

[img]http://upload.streetlegalmods.com/image ... 74788n.jpg[/img] [img]http://upload.streetlegalmods.com/image ... 64825n.jpg[/img] [img]http://upload.streetlegalmods.com/image ... 33091n.jpg[/img] [img]http://upload.streetlegalmods.com/image ... 75391n.jpg[/img] [img]http://upload.streetlegalmods.com/image ... 21858n.jpg[/img]

i changed Z lift to .6mm

i change retraction from 5.6 to 8mm

I changed it so it doesn't push extra when returning the filament back from retraction since this stuff is quiet springy and keeps extruding even when u retract it

I changed extrusion temp to 244, it would only get up to around 241 though.. it was struggling and I know thats really the limit.

I upped the speed to 40mms all around, could that of helped it?



why does it look so much better? is printing one by one a better idea, but then, im not sure abuot that because i've had these bad results as mentioned above when printing just one of these... whats going on with that?


It wasn't dragging really on the print but I felt like it was pretty damn close to doing it

I have no experience printing with nylon, but everything I read about nylon says the moisture is usually the culprit when results change. How are you storing your filament? Is this a new roll or one that has been open for some time? Have you dried it?

No I haven't, it does crackle a bit when printing, I wasn't really worried about it because I don't need the prints to be super smooth, just the right size and there is a tolerance allowed with this part.


Either way, I want to start putting all my filaments together in a container and run a portable dehumidifier.


I'm not sure thats the cause for these problems though.

I am hoping to have my E36 Chumpcar ready this summer.

I suppose this bushing has to be made of nylon or teflon and not ABS or PLA in order for it to behave like a bearing.


[img]https://fbcdn-sphotos-d-a.akamaihd.net/ ... e0c7aad394[/img]

Trivia: the inner shaft these bushings are riding on what is called the 'Bitch Clip'. Spending a half hour to take the clip out is not unheard of [ and might be typical for your first time ].
This photo must have been taken with the tranny out of the car. With it in the car you have maybe two inches between the where the clip is and the bottom of the transmission tunnel.
I have always had to drop the transmission mounts in order to get another couple inches to work in. This clip has to come out if the tranny is coming out, like if your putting a new clutch in.

The Bitch Clip: what every BMW owner hates
[img]http://www.autohausaz.com/secure/PartIm ... 221849.jpg[/img]

Yes, use an overly complex part in a near impossible to reach spot when a cotter pin would do the job.

g.

Actually a cotter pin to hold the big pin in would also be a PIA, because you can't really see this when the tranny is in the car. getting a cotter pin in a tiny hole that you can't see or feel would be worse than the bitch clip. At least you can put the bitch clip in easily. Taking it out easy[er?] can be done if you have a short flat screwdriver, or better yet a medium length flat screwdriver with a 45 degree bend in it. (right, a custom tool for one job. BMW has lots of those - I bought a Chinese clone of a cam timing tool for $400, BMW sells it for $1200 or something stupid).

geneb wrote:Yes, use an overly complex part in a near impossible to reach spot when a cotter pin would do the job.

g.

Hey! You have worked on airplanes!