ColorFabb LW-PLA (Expanding/Foaming PLA) Filament for FDM 3D Printing - Part 1
Hello everyone, Richard here - In this blog post I'll be looking at a new and unique 3D Printing material for the FDM/FFF process.
I have done a lot of testing and experimentation with this material, so if all you want to know is my opinion about using it for a few months, then a quick TL;DR overview summary is below, (and also just to the bottom of the blog for a summary and setting you will need) but I do hope you find the rest of the blog post interesting as it may give you some ideas of what you could do with a unique material like this.
One of the very first test prints of the ColorFabb LW-PLA - to work out the 'puff-point'
TL;DR Overview Summary -
LW-PLA is a really unique material for 3D printing. It's somewhat challenging to initially set-up, but when calibrated to your 3D printer, it can produce great results and most importantly light weight 3D printed parts.
You can print in both it's natural state, just like solid PLA, and with increased temperature a foamed state, so the same part can contain solid and foamed layers or features, it's like having a multi-material in a single filament. Foaming and density can be controlled by temperature and flow.
These parts can be further processed and finished, painted or coated as required.
Don't use in a machine with a bowden extruder system.
You will probably need a bed adhesive, It's not quite as sticky as normal PLA, I found Magigoo worked well, and slow down your first layer about 20% lower than normal PLA speed.
Be careful with extruder retraction – too much will make the filament expand beyond the thermal break and block extrusion flow.
In it's non foamed state, it's very similar to PLA, maybe a little more impact resistant. In it's foamed state it can be sanded, painted and sealed, very easy to post-process.
The foamed printed parts look and feel fantastic !
Quick Jump Index -
I have wanted a filament like this for many years, I have been doing a lot of material properties testing, experimentation and printing of parts. For that reason my blog post is going to be at least two posts, maybe more.
Part 1 - (This post) - Experimentation, foaming calibration and initial strength / weight testing.
Part 2 - (Next post) - Printing more parts, further strength testing and post processing / painting etc.
Future More... - Mixing? / Colour? / Crazy settings and big nozzles...
LW-PLA Test Material -
Much of the initial testing was completed on a Prusa i3 MK3, the beta material supplied by ColorFabb was a reel of 1.75mm ~750g 'Natural colour' it's also available in Black. Tolerance and roundness of the filament was good.
Note:- If you print at 50% flow, it's like having a 1.5kg spool of printed foamed objects 'by volume'.
Start settings and advice from ColorFabb -
ColorFabb included some guidelines and testing results with the Beta spool, showing how to calibrate a single wall cube line width so it is as per your slicer settings. This step is important if you wish to print parts that fit together and generally make accurate, repeatable foamed objects.
A primary focus in on the weight reduction of parts because of the foaming, but I was also very interested in the ability to make both hard and foamed features with just a single material.
Simple check to see what the foaming looked like – compared to normal ColorFabb PLA/PHA
My first test was to see the foaming in action – above is a cube printed with a low level of infill, you can see the outer walls, they were 3 x 0.44mm perimeters and the infill is a single wall and rectilinear infill causing the ridges every other layer.
After printing it was cut in half and the cut edge sanded so you can see the expansion above.
The Gcode started at 200 Degrees C and for each layer increase in temperature to 265 Degrees C.
Because this was printed with normal PLA settings and 100% flow rate, the material had no where to go, so both the outer perimeters and infill became many times wider as the temperature increased, eventually resulting in a temporary nozzle jam that corrected itself before being stopped at 265 Degrees C. This simple print told me a lot about what was going on with the material expansion due to just a temperature increase.
Checking the 'Puff-point' -
A simple change of temperature every 5mm layer height, shows the change from PLA to foamed PLA.
You can even change the temperature by just 3 Degrees C and trigger the foaming expansion point, showing this material has a good degree of control and repeat-ability.
At this point I have worked out various stable speed settings, so now to try and tune the extruder retraction and temperature I am happy to print the foamed material with - (spoiler alert – there is no magic extruder retraction distance that solves ooze).
After some testing with 'normal' PLA settings and just increasing temperature, you need to start matching an extrusion speed (stable as possible) with flow rate and also temperature.
As ColorFabb stated in the guidelines, you need to calibrate both flow rate and temperature to get a known and predictable rate of foaming expansion (rates of material deposition volume is also a critical factor). So that's what I set out to calibrate next.
The above is a test object, with hex infill and 100% flow rate.
Below is the same object, but a 50% flow, slightly lower temperature and greater extruder retraction
As with all material testing, you end up printing out a lot of test objects with various settings to test the limits of the material and the machine.
I spent some time trying to get a perfect extruder retraction setting, but it didn't take too long to come to the conclusion that it's almost always going to ooze if you are doing travel moves and not just 'vase mode' printing. Bu tit was very interesting to get a feel for the material, and experiment with line width settings, flow rates and temperatures.
It's also very tempting to change multiple things because you think you understand what's going on - it's often much better to change just one thing, then you will start to understand what's going on.
The final 'puff-point' test for me was to settle on a temperature I wanted to use for more adventurous printing, I decided that 225 Degrees C gave me a good level of foaming, and also minimal ooze. Again with 100% flow rate, but in 5 Degrees C steps (Image below).
This 'puff-point' will depend on your print speed settings, so you may well find that you see similar results as above, but at a different temperature range. I was running at around 40mm/sec for most print settings, and I found that to me quite optimal for using this material as it helps keep the puff-point temperature low (225) and that also keeps ooze to a minimum.
You can go crazy with high speed, high temperatures (250+) and you may get a 3x expansion or more, but I didn't find that to be useful when printing more complex objects with infill and islands - read on below to see more on that aspect.
With the above tests and more shown below I worked out that too much extruder retraction can cause nozzle jams and also does not stop the material from oozing - more about oozing later, as it's really not as big of a problem as it first sounds with this particular material.
After the 'test cube stage' - (Nozzle Jam #1) -
At some point you need to print more than test cubes, and for me the real test was going to be complex objects that had a lot of islands, long travel moves and a lot of start-stop retractions.
A good test object is a quad-copter (drone) body (design by DV0001) – it needs to be light, strong and has a lot of individual islands, large print area and plenty of extruder retractions. To test my theory of extruder retraction distance and high temperature, the above image shows an early nozzle jam failure.
This model proved to be a perfect (difficult) test for the foaming material, if I had started printing with an easier model I would not have learned so much about the 'viable window of usage' and I bet I would have ended up having a lot more frustrating failures later on without understanding why I was seeing jamming etc.
This was also the first indication that a high flow rate flow rate, combined with higher temperature (giving a high expansion rate) and low layer height could be making nozzle jams more likely (when you also have long extruder retractions) - so I set out to discover what were bad combinations and what were better.
Nozzle Jam #2 – (Learning all the time...)
After a tweak to the settings (see above in image), lower temperature(230 degrees C), increased layer height (0.25mm) and lower extruder retraction (3.0mm) and a lower flow rate (50%) - The print made it much longer into the print process, but still caused a nozzle jam before the print was completed.
Print success (No nozzle jams) –
Also don't be alarmed by the strings & loops - I will explain why that's not a problem.
Critical print success settings for me were –
Low extruder retraction (under 2.8mm) - I now use 2.6mm extruder retraction on all foaming prints.
225 Degrees C with a matched 45% flow rate
~44mm/sec Print speed on as many settings as possible (32mm/sec for small perimeters)
Higher layer heights (0.25mm to 0.35mm) worked better for the foaming process without causing nozzle jamming.
After I decided on these settings, along with a print speed of around 44mm/sec and going no lower than 32mm/sec (apart from layer 1 – that's also printed slightly cooler), I had no further problems at all with nozzle jamming or print failures. Every other print from now on was a first time success.
Foamed Benchy - Success!
MasterSpool Success ! (Again, don't worry about the ooze-hairs on the print – they rub off)
Both the drone body and a two part MasterSpool print are significant sized object, with a lot of features, islands and travel moves.
You can see some bumps and spots, but they just brush off. A little nozzle ooze is the one aspect of this material that is going to be almost impossible to eliminate, but in reality it does not seem to cause any problems for the printed object or the final finish after a little post processing.
A little bit of clean up -
The internal stringing 'hairs' and excess material looks to be a problem, but it's surprisingly easy to remove with just your fingernail, scraper or a blade. Removal does not leave missing areas of print or significant blemishes on the printed part.
The drone model and MasterSpool prints had quite a few hairs due to travel moves and oozing. But they clear off the model really quickly, most with just a brush of your finger or finger nail.
Straight off the printer, you are going to see some hairs and stringing, these are easily removed.
A light sanding will remove most surface imperfections and you won;t even be able to tell it's been sanded because it all feels the same as a very slightly textured surface. It's hard to describe, but I going to say that most people will really like the feel of the finish using this material.
At this point you may be thinking that you don't want to print at 'big 0.35mm layers', but the printed objects do not in any way look like models printed at 0.35mm layer heights...
You really need to see it in person to appreciate how nice a 0.35mm layer height can look on a model -
Next post - Firmware and Duet 2 setup - Scripting and ToolChange processing.
Lets dive straight it -
This is what we are aiming for when complete - Wiring (image above) and completed assembly with tool heads (image below) -
This blog post will cover the assembly and wiring of the ToolChanger.
Assembly documentation for the Beta30 machines was produced by Greg at E3D, this consisted of five separate documents for the various stages of the assembly and wiring.
I will loosely follow the five different sections as it also makes sense to focus on these areas when showing how the ToolChanger has been designed.
1 - Motion System Assembly
2 - Tool-Changer Assembly
3 - V6 Dock Assembly
4 - V6 Bowden Tool Assembly
5 - Motion System Electronics
Motion System -
I followed them in the above order, you can do them in almost any order you like, but it's well worth reading all of the documentation first before you begin any assembly.
You will need to gather tools, some materials (like metal banding) and other fixings, super glue and a bunch of other things.
Firstly if you build up a machine like this, be aware you probably need to buy some thread-lock fluid. Many steps are using metal parts, nuts and bolts that require a smear of thread-lock to stop them coming loose in use. Don't skip this advice, it's going to save you a lot of trouble down the road when you have your machine running.
Quite a few different things need to be thread-locked, so it's well worth trying to do as much as possible all at the same time. You need to leave 8+ hours for the thread-lock to set, so it's highly frustrating to complete some steps, then wait and then find you need to do more and have to wait again before you can finish the assembly. Give yourself a few days to complete the assembly, and another day at least to do the wiring.
You do get (almost) all the fixings you need to build up the ToolChanger - some (like 50mm M3 bolts) need to be sourced yourself, and a few E3D have already decided to add into the next round of kits to make it easier for people.
The frame construction is easy, you just bolt four vertical 30mm x 60mm aluminium extrusions - one in each corner to the base sheet of 4mm aluminium plate.
The back acrylic sheet is supplied - and E3D are considering also supplying the side panels in future ToolChanger Kits as they add a lot of strength and rigidity to the machine when built. Most of the Beta30 testers needed to get their own side panels cut locally. I was very kindly sent a set by Greg cut by E3D.
Fix on the back acrylic sheet - all the electronics, extruder motors and wiring mount onto that.
The motion system plate can be mounted on top of the four vertical extrusions, and bolted down - not to tightly at this point.
The Z axis module is next to be fitted - in between the top and bottom aluminium plates.
It's securely fixed with the Z drive motor at the bottom.
The build platform is is fixed to the Z axis carriage next - again it feels nice and solid.
Tool-Changer Assembly -
Next to be assembled was the main tool dock for the ToolChanger X/Y carriage -
The tool head consists of a Z-probe switch, high quality (metal geared) micro-servo and a rotating rod with locking pin to clamp down (as it rotates) gripping a tool on the kinematic coupling plate (far right plate in the picture above).
The servo is small but mighty, and it's geared achieving even more pulling power - the grub-screw is just too small - that's one thing E3D are going to change in the next batch.
You just fit some M4 metal spacers on the motion system carriage, add the servo, Z-switch and locking pin with thrust bearing etc.
A few early builders had some issues with the servo wires getting pinched and shorting out on the aluminium parts - so I added shrink-wrap around the servo cable.
Before adding the cover, I also routed the cables and wrapped the servo wires to the servo body with kapton tape.
The front and back parts of the pick-up head are mounted - and a drop of superglue holds in the locking pin as the grub-screw felt a little inadequate for my liking.
A simple printed safety cover fits on the the back to hide the wiring and cable entry point.
V6 Dock Assembly -
The tool docks are fitted on to the back of the machine, they hold the tool ready for a pick-up by the tool head we just assembled above.
Not too many parts for this section - just a matter of following the assembly instructions - easy.
Easy to assemble - but again need a drop of threadlock.
A pack of thin shims were provided to help vertically align the tool docks. It's very unlikely they will be needed for the next batch as machining and alignment was so good for this batch.
V6 Bowden Tool Assembly -
The tool assembly is a little more involved, and for the initial machine setup I'm using 4 x E3D V6 hot-ends - Configured in a bowden Titan arrangement.
Get everything you need for all the tools you are building.
And build them all up together - it's quite a few steps, and you will need to also check on the normal hot-end assembly instructions.
Some cables will need to be cut - (if you cut down your heater cartridge, make them slightly longer then shown above - I found 150mm was a better length - after cutting the first one to 130mm)
Each tool head has a small PCB (that may not be the case in future ToolChanger kits - so do check).
You are then just building up V6 hot-ends and adding them onto the supplied coupling plate (fitted with 8mm steel ball bearings)
The connector PCB gets clamped in between two 3D printed parts and bolted down.
Here I found it very useful to use longer then specified bolts so you can remove the cable clamp - easier to install and essential if you want to remove a tool-head.
Repeat 3 x times
And that's a set of V6 tools ready for the machine. (These are still missing heater blocks in the image above).
The tools just slide on to the docks we assembled in the previous section, and can be connected up up to the Titan extruders with a length of 4mm PTFE tube and wiring to the duet motor drives.
The Titan extruders are easy to build - just be aware you need 2 x normal and 2 x mirrored Titan's for the ToolChanger. (1.75mm - were used in this machine)
Another thing to be aware of is that the acrylic back panel is 5mm thick, so all Titan screws need to be +5mm longer to reach the NEMA17 motor holes.
Because of the acrylic panel thickness you can set the extruder gear to 13mm distance from the motor shaft end (as long as you are using a 0.9 degree NEMA17 Titan motor as supplied by E3D).
Do them all at once, and I always put a drop of superglue on to my gears and the grub-screw to keep things securely fixed.
Check the fit (before you superglue !) and then mount on the acrylic back panel.
If you don’t already know, the team at E3D have been working on a multi-tool 3D printer for quite some time. Greg Holloway, the designer of the E3D BigBoxmachine has brought life to a mechanical, electrical and tool-chain reference design platform they call the ‘ToolChanger’ – There is a really important statement here – it’s a reference design– NOT a finished 3D printer / machine or intended to be a 'final' system. Let me tell you why I think that’s a really good thing...
The FDM (FFF) 3D printing eco-system is on the cusp of a fundamental step-change. The basic too-chain from model creation – export – slicing – and printing with well controlled material, is now finally mature enough that even for basic low-cost machines, it works for most people.
Regular improvements in understanding melt-flow of plastics, electronics, firmware and sensors have made multi-axis systems operate fast with improved reliability and repeat-ability.
But we already have multi-nozzle / multi-colour 3D Printers? -
A number of options exist if you want multiple colours or materials in a single print – the Prusa MMU switcher, The Palette splicer, BCN3D IDEX or multiple print heads.
The difference with a ToolChanger is that the entire tool can be swapped during a print – for two or many different tool-heads or nozzles / colours / materials, even devices that cut, measure, buff or insert objects into your 3D prints.
Why Now? –
Plastic extrusion tools (extruder+nozzles) have now become optimised for a wide range of materials and temperatures – with a good level of reliability. The next step is to add in more of them, and also other tools that can do more than squirt out melted plastic. A ToolChanger starts to look more like a desktop manufacturing system, rather than ‘just another’ 3D printer.
I'll talk more about why it's the right time to be switching to ToolChangers in this series of blog posts as the machine gets built up and then tested.
As with everything - read the documentation...
Preparation before the ToolChanger kit delivery -
You may decide to pre-order a ToolChanger after the Beta30 trials have completed - if you do, you will most probably still need to print out a set of 3D printed parts for the system - (they may change, but here is what the Beta30 set needed).
You don't need all that many parts as most of the precision machining is all done by E3D and supplied as CNC aluminium parts or pre-assembled motion system modules.
The parts required are all very nicely designed - to print easily and also fit to the ToolChanger perfectly.
This machine does use mains, both for the SMPS and the Heated Bed, so it's nice to see even the mains inlet covers can be 3D printed to hide away the high voltage connections.
Step 1 - Unboxing -
Plenty of boxes, but all well packed and labelled.
Many of the ToolChanger parts are common E3D components or modular assemblies.
Like the Titan extruder and the V6 Hot-ends. - You just need to have four of them :)
The main Motion system is already assembled by E3D - this is all mounted on a very solid and flat aluminium plate.
The Z axis is also pre-assembled - you just need to bolt it to the top and bottom aluminium plates.
All quality machined parts - and E3D are also using genuine HIWIN rails for X, Y and Z motion.
Bottom plate - this is not a light reference machine, but it is solid, stiff and should print really, really fast if required.
The heated bed is directly powered by ~230v AC @ 800w - this thing is going to heat up fast and also expand as it heats.
The E3D heatbed has the silicone cured directly into the partially-anodised aluminium surface of the build surface - it makes a solid bond, not just stuck, but fused to the metal.
I spent a good few hours just getting all the parts out, and looking at the amazing machining, and design, thought and detail that has gone into this project.
The E3D ToolChanger has been over two years in the making - and it shows in every single component.
E3D really are pushing things forward for everyone here. I hope you support them - and yes they want people to design more ToolChanger systems. They also want companies and their partners/customers to consider using their tools and tool-plates in their own machines - after all that't the point here - to define an eco-system of tools and electronics / firmware support - without a drive forwards, we will be stuck with what we already have.
That's all for the introduction, join me next time and I'll start to assemble the ToolChanger motion system.
And don't forget to check out some of the other Beta30 ToolChanger builds - some are already built and printing out multi-tool 3D Prints.
These links below are borrowed from the Recent E3D ToolChanger blog post - if you are building up an E3D ToolChanger and want to be listed on my Blog, just let me know and I'll add you into the adventure.