The Watkins Blog

3D printing takes AGES! Even something as simple as the small container shown below takes four hours!

A lot of lessons were learned from this print job. The short version is as follows:

• Don’t start a print job at 8pm. You’ll get a late night.
• Supports are a great idea.
• The raft underneath was a waste of time on this model.
• The box is flimsy. See below for why.
• My Cura settings were wrong.
• The nozzle was still slightly blocked (as I found out a few days later).
  

3D printing involves layering tiny amounts of hot plastic, in layers of 0.1mm (or more, or less, depending on the printer). The software takes a 3D file (like a .STL file or a .OBJ file) and “Slices” it into hundreds of layers. This takes time. The white box above took nearly four hours to print, and I got to bed at midnight.

The observant will notice that the top of the box is a different colour. With 12 minutes to go, the white filament ran out. I cheekily pushed the end of a yellow length of filament into the top of the filament feeder, whilst it was still running, guesstimating the correct time to do so. I’m sure one is supposed to pause the model whilst doing this, but it worked for me this time.

The resultant box has weak sides, and feels flimsy. It feels like it’s made of thin paper, and the quality of the sides is terrible. There are two possible issues: one is that my settings in the Cuda software are incorrect. I’m using Cuda to add supports and the raft – because the official Digilab software won’t export in the correct format. the other issue (as I found out) was that the nozzle was still blocked.

The underneath of the box is much better than last time. Apart from a few stringy bits, it’s relatively clean. The supports were very thin, as they are meant to be, and broke off easily.

I’m not convinced that a raft was really necessary. It took 31 minutes to print the raft, even before starting to print the supports and the model. I felt that the raft was a waste of time in this case. There are good examples where a raft is important, particularly for models which don’t have a flat base.

Next, we will try giving the nozzle a really good clean, and try again.

After printing a stringy mess, the nozzle of my 3D20 is covered in goo (filament). At room temperature, it’s a nice hard crusty smooth goo. The instructions explain how to clean the nozzle. There’s a nice video (with jolly music) that shows how to do it too:

• Put the printer in heat mode to get the nozzle up to the correct temperature.
• Don’t touch the nozzle – it’s 220 degrees C.
• Remove filament from the top of the print head.
• Don’t touch the nozzle. It’s hot.
• Let the filament ooze through the nozzle for a bit.
• Did we say the nozzle is hot?
• Poke the cleaning tool in at the top and push out any filament.

I did this, and the cleaning tool went quite deep into the print head, almost to the nozzle. Then I pulled the cleaning tool out, and as I did so, I realised something had gone wrong. It felt like filament had been pulled out with the cleaning tool. I tried poking the cleaning tool in again, and it wouldn’t go. I guessed that the filament had solidified on the top of the metal part of the print head.

As expected, I’m not the first to experience problems like this. Here is a video, (with no sound), showing how to dismantle the print feeder, to get at the print head. Be careful not to loose the nylon spacers behind the heat-sink, behind the fan.

With filament back in the machine, a print job could be started. The results are shown below, and I’ll talk more about it in the next post.

The SD card with the correct software was missing when we bought our Dremel 3D20 (it was a bargain). But I found the “Dremel Idea Builder” software and a firmware update on their website, and that allows me to load STL files, and send them to the printer via USB cable.

Unfortunately, the “Idea Builder” software has no option for adding supports to a model. Supports are needed so that the nozzle doesn’t print filament over an empty space.

However, Dremel now offer a new Slicing software called “DigiLab Slicer“. This is easy to use, and has options to add supports, rafts, skirts, change the print quality, and do the slicing. It saves in .gcode format. It is based on the open-source Cura software.

This is all good news … except that Idea Builder doesn’t like .gcode files. It needs its own special format of .g3drem. And DigiLab Slicer doesn’t save in .g3drem format. It would appear that I’m not the only person with this problem. Dr. Peter Falkingham, university lecturer in vertebrate biology prints models of animal bones for use in his lectures. And he has had the same problems: most slicing software can create .gcode files. but how do you create a .g3drem file?

Update 15 March – I emailed Dr. Falkingham, who clarified that the latest firmware allows the 3D20 printer to read .gcode files off the SD card. The problem I experienced exists when printing from the “Idea Builder” software via USB cable: “Idea Builder” does not read .gcode files.

Further online searching revealed that others had the same problem too. One guy wrote a plugin for Cura that saves to g3drem format. A quick installation of Cura, then a visit to the Cura Marketplace (from within the Cura software), and the plugin is installed. It isn’t supported by Cura, it comes with no warranty, except that your printer might catch fire, but I’m happy with that.

So now I can create supports for the model from the STL file, save it as a .g3drem, and load that into Idea Builder to send it to the printer.

Except that the nozzle is blocked. That’s a job for another day.

Our 3D printer (Dremel 3D20) was a bargain, because bits were missing. After five emails to Dremel support, and various phone calls, I eventually found a supplier who was willing to order the spare parts that I need – mainly the spool lock so that the spool of special Dremel PLA will rotate freely.

Using some of the spare filament that my dad gave me, I attempted to print a small box. This box has feet, so the area touching the build plate is relatively small, and the bottom of the box is off the ground. After about 15 minutes, the printer had created a stringy mess and had pushed the model sideways on the build plate … and was now attempting to add fresh filament on top of empty space.

The main lesson learned today is to add supports to the model before printing it. That’s a job for another day.