Typical in-school problem: replacing Replicator 2 screws and small plastic parts

[pzingg]

I'm the tech director at our school and I've got some time to help our makerspace teacher figure out why both of his Replicator 2's don't work. The first one has got a real problem, from my novice point of view--it's missing screws, the filament blower fan (the big plastic centrifugal fan on the left side of the extruder assembly) is not correctly fastened, and the small plastic duct that is supposed to aim this fan's air at the nozzle is completely missing. Also one of the long Allen-head bolts that keeps the extruder together with its heat sink and fan is gone, so that might also be a problem.

Replicator 2 fan loose.jpg

The symptom on this one is that it consistently starts laying down PLA, but after about 0.5 mm of material has been deposited, the extruder stops emitting material. The front panel says that the extruder temp is OK at 230 C plus or minus a degree. I'm guessing that having this fan bit bent off to the side, the filament gets jammed. (Or else the extruder drive gear stops working, or the temp has actually gone down even though the panel says it's OK, or something else?).

Since the Replicator 2 is really an old beast by now, I'm wondering where or how I can obtain these missing parts. I have seen that folks 3D print the fan duct piece, but I don't see any information on how the blower fan is supposed to be attached to the extruder block, and I don't know where I can get the missing Allen-head bolt.

Any ideas?

[Sebastian Finke]

1) Sounds like someone's vandalized/cannibalized your printer. Replace the missing parts asap as the heatsink need to be fitted properly. Part that can be printed may be found on Thingiverse. The bolt should available from any hardware supplier. It is an M3 bolt, I can't recall the length though so you may need to remove the second one to measure it (NOTE: capscrew lecgths are determined by measuring only the shaft, no the cap!)

2) 230 is way too high for PLA. Its likely that PLA got burnt has caused a blockage. You may need to strip the offending nozzle to clean it out properly.

[Mjolinor]

You would probably have more luck finding the missing "allen head bolt" if you googled "socket head screw" or "socket head bolt" which is what it is called, once you decide whether it is a screw or a bolt.

[Davo]

They're essentially interchangeable, although technically a screw is a threaded fastener intended to be seated in a fixed medium (like wood, metal, etc.), and a bolt is a threaded fastener intended to take a removable anchor (like a nut). At least in US usage.

[Mjolinor]

A bolt is not threaded up to the head and therefore has a constant diameter shank suitable for accurately locating two parts that need to be registered in place, a screw is threaded all the way to the head.

That is the engineering definition irrespective of country and the countries tendency to change the meaning and spelling of words.

[Davo]

Some wood screws are not threaded all the way to the head; some hex bolts are. Otherwise your definition correlates with my experience.

EDIT: See "What Every Member of the Trade Community Should Know About: Distinguishing Bolts from Screws" at http://www.cbp.gov/sites/default/fil...s/icp013_3.pdf for US standards.

[pzingg]

1) Sounds like someone's vandalized/cannibalized your printer. Replace the missing parts asap as the heatsink need to be fitted properly. Part that can be printed may be found on Thingiverse. The bolt should available from any hardware supplier. It is an M3 bolt, I can't recall the length though so you may need to remove the second one to measure it (NOTE: capscrew lecgths are determined by measuring only the shaft, no the cap!)

2) 230 is way too high for PLA. Its likely that PLA got burnt has caused a blockage. You may need to strip the offending nozzle to clean it out properly.

OK. Thanks for the tips. I'll look for that replacement M3 screw and reduce the temp. I found this on MatterHackers - PLA Temperature Quick Reference:

Color Recommended Temperature Recommended Range
Black 195c 190c - 210c
Glow-In-The-Dark 190c 185c - 205c
All Other Colors 210c 205c - 220c

New Question: Does the Replicator generate any logs regarding nozzle temp or other operations (whether filament gear motor is on, rate, etc)?

Also I'll try to understand how the big blower fan on the side is attached to the printing block structure and attempt to secure it. Maybe I can get the printer to work well enough to replicate the fan duct part...

[Mjolinor]

Some wood screws are not threaded all the way to the head; some hex bolts are. Otherwise your definition correlates with my experience.

EDIT: See "What Every Member of the Trade Community Should Know About: Distinguishing Bolts from Screws" at http://www.cbp.gov/sites/default/fil...s/icp013_3.pdf for US standards.

If you think you have a bolt that is threaded all the way to the head then it is a screw, not a bolt.

A screw:
http://blog.mutualscrew.com/blog/ass...-diamaters.jpg
A bolt:
http://www.ahc-camberley.co.uk/media...inc_plated.jpg

[curious aardvark]

surely a screw is a tapered fastener designed to burrow/drill into something point first. And a bolt is a non-tapered fastener designed to couple with something possessing an existing thread.

That aside, pretty much any hardware store will carry a variety of m3 bolts (non tapered) Think the ones I use have cross phillips type heads.
That said I remeber I couldnt find any in b&q or the other large diy store in burton and got them instead from the proper aisan hardware store in swadlincote :-)

Also amazon I've bought them from.