Multi Color Prints, Fine Tuning, colorFabb and FreeCAD

by Jason King on September 16, 2014

Two Color 3D PlaqueWelcome to the latest instalment in my new 3D Printing Beginner Series.

I did so much 3D printing last week that I couldn’t cover it all in one reasonably sized blog post, so this is kind of part two.

There’s lot of good stuff to cover in this post so lets continue right away, starting with multi color printing.

Although I’d heard of using a single extruder printer to create multi color prints I’d never really given it much thought until recently, when I noticed the Pause option on the MakerBot menu.

After pausing a print and resuming a few times I then noticed that you could also change the filament before resuming. Viola, we have basic multi color printing.

Ok so it’s very limited because you can only use different colors for different Z-axis layers but where you want a different color for the upper part of a print it’s great. Typically this could be a plaque/keyring with raised writing on, or even something like a black fishing float with a bright orange top. There are multiple uses for this feature.

A few test prints later and I noticed the “Z Pause Height” option on the MakerBot menu too. This only seems to be available once a print has started, but it allows you to automatically pause a print at a given height in millimetres. This means you can swap colors at a precise height without having to supervise the entire print.

This is a great feature and one which I’ll be using a lot from now on. One thing to note though. When you start a new print sliced with something like MakerWare it’ll start by extruding a line of filament in order to help clear the extruder before printing.

This doesn’t happen after changing filament during a print, so try to ensure there is minimal plastic hanging from the nozzle before you resume printing. It’s not critical and any initial excess can usually be removed from the print afterwards, but it does help create a cleaner print.

Custom Profiles for Fine Tuning Your Prints

In previous posts I have stressed the importance of Measuring Filament Diameter. There are many reasons for this, but the main one is because your software will use the filament width to calculate the exact rate of extrusion.

WakerWare Custom ProfileThin filament will extrude too slowly and thick filament will extrude too quickly. Within reasonable limits you can correct this by telling your software your filament diameter, which you can work out by measuring it in a few different places with a vernia caliper and taking the average.

So, how do you tell your slicing software what your filament diameter is? In most slicing software there’s a field on the interface where you can enter the value. Unfortunately, MakerWare is the exception and there is no such field.

Don’t stress though, when you click on “Make” from within MakerWare you’ll see an option to create a custom profile. When you do this you can manually edit a settings file which opens up a whole new world of hundreds of settings, including “feedDiameter” which you can update with your filament width (to the nearest 1/100th mm).

This file may include a couple of hundred settings but don’t be scared by it, just update the “feedDiameter” setting for now and then take a look at the other Slicer Settings on the MakerBot Website.

There are settings for two extruders by the way, even if you only have a single extruder on your printer. If you have a single extruder it will usually default to the first set of settings, or just update both if you wish.

An Example of When You Need Supports

Whether you’re designing or downloading things to 3D print you’ll need to know when and where your design requires supports.

When designing my own objects I try to design them to not require supports at all but it’s not always possible. When 3D printing things I’ve downloaded I also need to know whether to turn on the support options or not.

Obviously none of this is possible unless you understand when supports are needed and when they’re not, so let me give you some simple examples.

One way to help decide when supports might be needed is to learn the “YHT” rules. Let me explain…

  • Y – external slopes of less than 45 degrees from horizontal may well need supports. Slopes more than 45 degrees from horizontal usually won’t. Think of the letter “Y” where it branches into two slopes.
  • H – bridges between two or more pillars, like the cross bar of the letter “H” usually won’t require supports. Even though your printer is extruding into mid air it will usually do a decent job without supports if there’s a gap to bridge.
  • T – overhangs like the cross bar of the letter “T” will always need supports. Your printer will be extruding into mid air, the cross bar is zero degrees from horizontal and there is no gap to bridge between two or more pillars. Without supports your “T” will fail every time.

Ok so I hope that makes sense but if not, I thought the best way to demonstrate this was to ditch the theory for a minute and to actually do it, so I did…

I printed these three letters, upright and filmed it so you can actually see the “Y” and “H” print well, but the “T” fail exactly as I described above. Watch my 3D Printing Slopes, Bridges and Overhangs Demonstration and it will all become clear…

If you remember these three simple rules of thumb I promise it will dramatically improve the way you design and 3D print your objects from now on.

Tinkercad Broken and colorFabb Filament

On the subject of designing, for some reason my favourite CAD program Tinkercad no longer works on any of my computers. I know Tinkercad is only a very simple CAD program with limited functionality, but I love simplicity and for quick jobs, like my “YHT” design/print above it’s excellent.

I’m pretty sure it’s not the fault of Tinkercad, it just seems that the Google Chrome browser I use has suddenly disabled or become incompatible with webGL, which Tinkercad uses to render the 3D images.

colorFabb FilamentAlways trying to turn negative situations into positive ones, I have taken this as an opportunity to learn a new and more complex CAD package, FreeCAD.

I keep hearing very good reviews of FreeCAD so it’s time I learned how to use it. Best of all and as the name suggests, it’s completely free too and we all like free 🙂

I’ve downloaded and installed it, but it looks like there’ll be quite a learning curve, unlike Tinkercad which took about an hour to master. I’ll keep you informed and if you have used it yourself and have any tips, please send them to me.

Even though my design capability has temporarily diminished, at least until Tinkercad is working again or FreeCAD has been mastered, I decided to buy some more filament.

If you haven’t noticed yet, most of the pictures in this Beginner Series are of objects in green or purple filament, just because I have lots of it. I have many different colors of the colorFabb filament, but only samples and not much of each.

So it was time to order some more, partly because I found a 10% discount code on Twitter, which unfortunately has now expired else I’d share it with you. Anyway, I ordered another color sample pack of ten different colors and then got carried away and ordered a full spool of Sky Blue, another of Dutch Orange (colorFabb is a Dutch company and orange is their national color), another of Fluorescent Green and finally a spool of Natural White (great for all those Dinosaur and Celtic Skulls).

When this filament arrives expect some much more colorful pictures, especially now I have mastered multi color prints too. I chose the colorFabb filament because it prints so well and the colors are glorious, but it isn’t too expensive. I now wish I’d have ordered some woodFill and bronzeFill too but never mind, next time.

Thanks for reading and feel free to Like, Share and Comment on this post. Also you can Download your FREE Beginners Guide to 3D Printing at Home eBook for more 3D printing tips.

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