All posts by jsng

I’m a technology enthusiast looking for ways for students to benefit from an informed and conscious use of technology in schools, at work, and at home. During my non-free time, I teach Physics and manage a 3D printing programme for students.

Project: Spool Holder bug report #1

Minor issues cropping up: now that the filament spool is nearing its end, it is getting lighter, and the sudden pull of filament from the extruder is causing it to shake. This could be bad if the spool topples over and obstructs the downward movement of the platform.

spoolholder-shake-1We will look into this after the exam period, but if you have any ideas we would like to hear them in the comments as well.

Advertisements

Project: Spool Holder (ver. 1.1) – printing with supports

Our new spool holder works really well, especially considering that it is only the first version. It rolls really smoothly and has not slipped off the bearings yet, thanks to the wall supports on the clips.

There are still some things we were unhappy with though. This is a changelog (i.e. a list of changes from the last version):

  1. Made the spool holder base 2mm wider for a snug fit with the cavity.
  2. Added sliding cutouts (these are known as dovetails) for fitting the clips to the base without any need for superglue.

spool holder clip

I added jigsaw cutouts to Zhuowei’s ver 1 design, so that we can slide the clips in and adjust their positions without having to fix them down with superglue. Learning from past lessons, this time round I added a 0.4 mm gap between the two objects (0.2mm for each object) to ensure that the fit would be just right. Continue reading Project: Spool Holder (ver. 1.1) – printing with supports

A note on ABS printing with the Flashforge Dreamer

Some notes from printing the fan speed selector cap in ABS.

High-temperature printing

ABS printing involves higher temperatures (extruder 220°C, print bed 100–105°C). For tall and thin prints, this means that the lower layers might not have enough time to cool before the next layer is printed. Over a number of layers, this means that the extruder may end up printing on top of slush.

If you look carefully, you may see the lower layers wobbling as the extruder head is printing on top of it. This is a clear indicator of slush-printing. You may need to pause the print for a short while (30 seconds) to let the layers cool before resuming the print.

This can also be minimised by lowering the print speed. The first fan speed selector cap was printed at 60 mm/s, the second one at 30 mm/s. (Print times were ~30 min and ~1 hr respectively.)

Edge curl

ABS tends to curl at the edges, especially on the first layer. Minimise this by raising the platform temperature, and lowering the print speed.

Preheating

The first few times I attempted to start the print, I noticed that the extruder head seemed to stop at a certain temperature. It turns out that the Flashprint first attempts to heat up the print platform, and only when the platform reaches its target temperature will the extruder head start to heat up. This may cause the initial heating time to be frustratingly long.

While you are still tweaking the design, you may want to get the Flashforge Dreamer to preheat first. A good start is the have the extruder preheat to 180°C, and the print platform to 90°C.

Be careful not to set the extruder preheat temperature too close to the print temperature (220°C), otherwise it may start oozing before the print!

Safety

While printing, be aware that the print platform is heated, and can burn those who are not careful! If you are supervising viewers, I suggest you keep the print door closed, and do not remove the print until the print platform has cooled down to below 50°C.

Problems: Sagging spool holder

Did you know that the Flashforge Dreamer doesn’t actually come with spool holders? There are two cavities, one on the left and the other on the right, in which the filament spools sit. But there are a bunch of designs for spool holders that can be printed to fit spools of various sizes. Our vendor, Simplifi3D, was kind to provide us with a set of two holders to start with.

One of the first problems we encountered while printing: the spool holder actually sags after some time:

2015-06-10 12.09.08 Continue reading Problems: Sagging spool holder

Introducing the Flashforge Dreamer

dreamer-i-1-web-nobg

So I heard you are thinking of buying a 3D printer. The options out there can be dizzying, but once you have a clear idea of what you want to have in your first 3D printer, the selection process becomes much easier. I eventually settled on the Flashforge Dreamer, made by Flashforge in Zhejiang, China. This is almost the exact same printer that Dremel is using as their 3D Idea Builder. This printer is available from Simplifi3D, a vendor based in Bras Basah, tucked into a corner on the second floor.

In this post, I will outline some of the deciding criteria that I used to narrow down my choices. Continue reading Introducing the Flashforge Dreamer