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Nick's 3D printer build
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Nick
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Nick's 3D printer build

My 3D scratch-built 3D printer shenanigans:

After using the Cocoon printer for several months, I am completely hooked - when it was down for repairs for a few weeks, I had 3D withdrawal symptoms Laughing. The Cocoon is a great printer for the money but I want something better, so a custom printer is being designed. There are many impressive mid & top-end printers out there but none of them have everything I want - at any price point. After watching many, many reviews I have a long wish list; let's see what is actually achievable:

Wish: Open source everything:
If it's not hackable, its just not interesting! Many of the best printers are completely closed systems, which is great for schools & business but not if learning and experimenting is high on the agenda.

Reality
100% achievable using Simplify 3D for slicing and the Azteeg X5 controller with Smoothie firmware. The Azteeg board doesn't get much press but it has impressive specs and the firmware is open and well supported.

Wish: Larger print volume
The cocoon's 200 x 200 x 180 is getting restrictive; I haven't come close to the 180mm Z hight but the build platform is getting too small and something larger is needed.

Reality
Material for a 300 x 300 platform is easily available and I compromised a bit on the hight with 220mm.

Wish: Print all the things with all the filaments
Printers that just print PLA and ABS, or have proprietary filaments are just not acceptable any more! Most printers will do an acceptable job with mainstream filament but I am aiming to use virtually ANY filament, including ones not even invented yet Smile

Reality
About 90% achievable; there are many different things that are required to print every filament, here is what I am going with:

* Heated enclosure: Stratasys may hold the patents but as a non-commercial builder, I am sticking it right up them! Having the enclosure heated to around 70 degrees C with make warp-free (or at least warp-minimised) prints with high temperature plastics like ABS, nylon and polycarbonate possible. Many ideas I saw on-line were really daft or dangerous, so some experimenting is in order.

* Dual feed extruder: having two feed rollers and a tight filament path makes printing flexible filament easy, There are few dual feed extruders on the market and the best looking one is from Bondtech. It also has a planetary gearbox for loads of torque to force stiff filament into the hot-end at high rates.

* All metal hot-end: an absolute must for high temperature plastic. I am going with the E3D V6 with the volcano heater block. This will heat virtually every plastic and extrude it a high rates.

* Hardened steel nozzles: abrasive filament like carbon fibre will wear out brass nozzles after just one roll. Getting hardened nozzles will allow all the metal and fibre filled filaments to print without wear & tear.

* Heated bed and buildtak surface: Pretty standard stuff nowadays, buildtak seems to be the closed thing to a universal print surface. The heater has a 300W power rating and I am backing it up with insulation to reduce the warm-up time.

Wish: auto-levelling platform
The inductive sensor costs under $4 and plenty of firmwares support levelling so I don't understand why it isn't a standard feature on all new printers.

Reality
100% achievable with a cheap sensor and the Smoothie firmware. To make it more reliable, I am using a 1/4" thick MIC-6 aluminium build plate; it has a milled flat top so once the bed is levelled at the corners, its levelled everywhere (unlike the warped bed on the Cocoon, which is a constant annoyance!)

Wish: fast printing
The Cocoon does 60mm / sec well and can be pushed higher, but the print quality starts to suffer. At higher speeds the extruder and hot-end can't feed filament fast enough.

Reality
About 80% achievable. The new printer is designed to be extra rigid and the fast-moving parts like the head & Y axis are being kept relatively light. The heavy extruder is remotely mounted and feeds filament via a Bowden tube. The Bondtech extruder has enough torque to feed filament quickly and the volcano end can melt filament at higher feed rates. As a bonus, the hot-end comes with up to 1.2mm nozzles to really rip through prototypes and larger prints.

The controller has a 32 bit ARM CPU, which can keep the motors moving fast without dropping steps. Most controllers still use the 8 bit Atmega chips, which barely have enough processing power for high speed movement.

Here are the parts that have arrived so far:



There is also a pile of aluminium sheet and extrusions for the frame. Before the smaller parts are machined, they are being prototyped in PLA. The finished printer will have virtually no printed parts, important when using a heated enclosure.
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Post Fri Jul 01, 2016 12:21 am 
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Nick
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Heated enclosure testing #1

There isn't much quality info about heated enclosures - a prime example of how patents crush innovation! That means designing and testing something from scratch; the two leading contenders are a hot air gun and a heating element used to stop condensation in electronics enclosures.



The heater is the aluminium part to the left of the fan. It is rated for only 200W, so the enclosure will need 2 or 3 of them to get up to temperature. The element by itself isn't much use - it will be mounted on a recycled heatsink and the hot air will be distributed with a recycled computer fan. The heater is inherently safe as it limits itself to 200 Deg. C and shouldn't be able to set anything on fire.

The heat gun is a handy all-in-one solution; it has three fan settings and variable heat so it can be tuned to deliver between 50 and 600 degrees. It has a 2000 watt rating which is more than enough. There is one deal-breaker though - it kills all the WiFi throughout the house when its switched on! I may be able to shield it with aluminium tape or a box but if not, the heat gun will be banished back to the workshop.

I plan to use a commercial temperature controller to keep the enclosure at a stable temperature.



Its a bit expensive at around $100 but WAY easier than making my own and I already have one to borrow from my urethane curing oven. Now I just need to find enough cardboard boxes to make a test enclosure.
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Post Fri Jul 01, 2016 12:18 pm 
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Cpnwolfe



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this gonna be good!
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Post Fri Jul 01, 2016 1:47 pm 
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Nick
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Let's hope so - its by far the most complicated thing I have ever tried to build, so there are bound to be mistakes along the way.

I found option 3 for the enclosure heater, its this element from a toaster oven:



Its about the size of an A4 sheet and I have three so its the cheapest option. Using an oven element means using a fan, just like in a fan-forced kitchen oven and its a safety concern to use something that can get very hot when its going to be running all night - I don't want to burn the house down!
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Post Fri Jul 01, 2016 2:01 pm 
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DumHed
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Bunnings have a tiny fan heater at the moment for $15.

It's rated at 500w, and has a PTC ceramic element and basically a computer fan in it.

https://www.bunnings.com.au/arlec-500w-white-mini-ceramic-fan-heater_p4441782
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Post Fri Jul 01, 2016 2:47 pm 
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Nick
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WOW, that is absolutely perfect, will be picking one up ASAP! Very Happy I definitely owe you one for that tip.

I bodged up a test enclosure but I am not going to test the other options until I try out the Bunnings fan:



600 x 600 x 450 made from old cardboard boxes - recycling at it's finest!
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Post Fri Jul 01, 2016 3:18 pm 
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Knightrous
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Following this with great keenness Very Happy
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Post Fri Jul 01, 2016 3:42 pm 
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Nick
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A slight diversion:

The Cocoon printer is producing rougher prints lately and its at least partly due to the wobbly Z axis metalwork. To firm everything up and bring the gantry back to square I built this massive plywood base and supports:





The wood is just sitting in place until I can mark out out all the screw positions. Once its all fixed in place, the printer will be MUCH stiffer and the added weight should help dampen vibrations as well as stop the gantry from rocking. I will add some handles to the base and stick the control box in place so the printer is more portable.
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Post Fri Jul 01, 2016 10:22 pm 
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Nick
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Big little heater:
The $15 heater from Bunnings is awesome! I picked up three; one for the printer, one for a workshop hand warmer and one as a spare. Its really small and surprisingly well built, here is what the insides look like:



The heater element is around 15mm thick and is clipped into a much thicker plastic shroud. There is a low power 12V fan on the back of the shroud (not shown) and the cutest little 12V power supply on the side.

The built-in fan doesn't have the power to blow air evenly around the printer enclosure, so its being replaced with the 80mm fan on the left. Annoyingly, the mounting lugs on the shroud don't quite match up with the fan, so either an adapter plate is needed or I replace the entire shroud.

Printer Y rails and build plate:

The prototype for the bottom of the printer is all done:



Its about as simple as you can get; the 1/4" thick MIC-6 aluminium build plate has a bracket carrying the linear bearings mounted on each side. There doesn't need to be any complicated levelling adjustment as that is handled by the firmware.

The downside to the super strong build plate and brackets is their weight. I have a higher power stepper motor that will hopefully be up to the job and it will use 10mm wide T5 belt with steel reinforcing to prevent any stretching with high loads and temperatures.
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Post Sun Jul 03, 2016 1:31 am 
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DumHed
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I'm surprised the fan in the heater has its own power supply!
Usually they just do something dodgy with a voltage divider as part of the heater element, or use a 240v fan.
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Post Mon Jul 04, 2016 9:51 am 
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Nick
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LOL, power supply might have been optimistic! It looks like they are directly rectifying 240V and then using a linear regulator, so everything is at mains potential. Its safe enough when buried in a plastic case otherwise pretty dodgy.

Compared to other heaters I have opened to repair, the general build quality is really good - its amazing for only $15.
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Post Mon Jul 04, 2016 9:59 am 
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DumHed
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ah right, that makes more sense. Wasted energy in a regulator is not an issue when you're a heater Smile

It looks like the heater elements are in parallel too, so you could run them in series for a lower power setting if needed.
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Post Mon Jul 04, 2016 10:33 am 
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Nick
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Good point, or they could be run off separate relays for a low & high setting.
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Post Mon Jul 04, 2016 10:39 am 
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Nick
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The workshop hand warming heater is a life saver! A couple of minutes in front of it thaws out my frozen fingers and after 5 minutes there is a great BBQ smell in the workshop Smile. This is how it looks in infra-red:



The 153 C maximum temperature is probably the front grille; when I get the camera really close it shows up to 196 when pointed directly at the ceramic elements. Notice that low temperature; 8.8 degrees at 1pm is positively un-Australian!!!
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Post Mon Jul 04, 2016 2:04 pm 
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Ondray



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As someone planning on building an enclosure for my new printer this weekend, I'm watching this intently. If your heating system works out I may just copy it Smile

Post Wed Jul 06, 2016 10:02 pm 
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