Fixing Z wobble, attaching a fan, and upgrading hotends

Fixing Z wobble

In my last post, my prints were suffering from heavy ribbing due to Z wobble. I finally caved in and purchased machined 5mm to 5mm couplers from Markerfarm to replace my old, ineffective Z couplers.

Unfortunately, I'm away from home, so there's no pictures available at this time.

From now on, I'll definitely recommend to everyone who has Z wobble to try and get the most accurate couplers possible before quitting. It really does make a world of difference.

Attaching a fan

To improve print quality even further, I wanted to attach a 80mm fan I salvaged from an old PSU. For those of you who don't know, the fan improves print quality of PLA prints by quickly cooling the rather soft and rubbery PLA so that it becomes hard and holds its shape. Otherwise it droops on overhangs, even with supports, which makes for an ugly looking print.

But I ran into two problems:

1. The Makerfarm wooden carriage doesn't allow for much to be attached
2. My fan is a 80mm fan, which is larger than the 40-60mm fans people tend to use for this purpose.

To solve problem 1, I searched for a fan mount for the Makerfarm carriage. Someone really smart decided to use the two screws on the side to secure a fan mount without damaging the carriage (seen here: http://www.thingiverse.com/thing:145065). Problem is, this one was made for a smaller fan, so I had to adapt it to a larger fan.

Long story short (will be covered in a later post), I modified it to fit an 80mm fan, and printed the part. It seems to be a bit tight under the stepper motor, but it works fine

I don't have any photos right now which shows off the improved print quality, but the overhangs don't droop anymore.

Here's the link to the part if you need it: http://www.thingiverse.com/thing:189177

NOTE: only works on Makerfarm i3 kits and 80mm fans. DO NOT print this if neither of these things apply to you.

Hotend upgrade

During Black Friday, Makershop NZ decided to discount their stocks of the E3D all metal hotend. I've been wanting one of these for quite some time, but got put off by the cost and wait time. Since this sale killed two birds with one stone, I went ahead and got it.

Once again, just a quick lesson on hotends. The J-head which came standard with the Makerfarm kits are quite robust and easy to use. However, they have a few issues which can be solved by upgrading.

Firstly, the J heads don't have easily changeable nozzles as the nozzle and heater block are made from the same piece of brass. This is a problem since I was stuck with a 0.5mm nozzle. A 0.5mm nozzle is relatively large, and while it's good for quick prints, it's not very good for prints with high details. The all metal hotend came with a 0.4mm nozzle which can easily be swapped out as needed.

Secondly, the J head is constructed with PEEK plastic in the barrel. This is because when plastic melts in the barrel of the hotend, it expands and forms a rubbery plug. PEEK has a low friction coefficient, so this plug can slide down easily without clogging everything up. Problem is, PEEK can only be heated up to about 240oC before it starts to soften, so these hotends can't be taken past this point. That's a huge problem when it comes to printing with other materials such as nylon, which has superior strength and low friction between parts. Since the E3D hotend is all metal with no PEEK, it can easily print any thermoplastic in the foreseeable future as it can withstand temperatures past 300oC.

Lastly, the surface quality with the E3D hotend is much better than the prints made with the J head. I don't know exactly why, but it could be due to the reduced ooze (dribbling of plastic while not extruding) during printing Alternatively, it could be due to the improved nozzle design, since I didn't need my cooling fan to print overhangs easily.

Sorry, no photos for now. I'll upload them once I get back.

Of course, these improvements come at a cost. The E3D hotend requires active cooling, so the supplied fan needs to be run continuously while printing. This is an easy requirement to fill, since I just snaked a few cables straight from the PSU to power it.

Overall, definitely consider swapping to the E3D hotend when you can. Highly recommended upgrade.