FlexionHT Extruder for the Wanhao i3

Over New Year’s I ordered the Flexion-HT extruder for my Cocoon (Wanhao) i3.

I really had a hard time using the various extruder mods you can find about the place attempting to print TPU.

I purchased mine paying the full RRP in Australia (ouch) from 3D Printer Gear in South Australia (the Aussie dealer). Flexion box had previously been unsealed before it arrived.

The Flexion is expensive but it has worked first time with no major operational headaches.

The online instructions don’t reflect the HT version very well (nearly no at all). For others following the online instructions here:

Single extruder

 

Here are my additional notes (read in addition to the Flexion site notes as of Jan 2017):

Flexion will be updating instructions shortly (Feb 2017) – so some of the following may appear superfluous!!!

For Step 2: Disassemble hotend

– The heater element wiring is stiff but brittle. Be careful with it and the thermistor.

– My heater grub screw had seized, I had to remove the block and use a tiny drop of WD40 on the screw for an hour to un-seize it.

– The supplied hex key/wrenches supplied with the Wanhao are very weak. My smallest one bent. Careful using ball ended wrenches, they can round the edges of the hex screw if not seated properly or if they are just a fraction the wrong size.

I intend to finally have both hot ends easily swappable with a dedicated thermistor and heater cartridge for each.

Step 3: Assemble hotend

– My kit was missing the M4 screws for the thermistor clamp, the originals are M3 and don’t fit. Found out later there is an M3 thread hidden under the silicone cover.

– Also missing were the two washers for the stepper motor (not needed for me – see Step 5)

Step 4: Install heater

– My heater cartridges (both original and ebay Chinese spares) were loose in the block. The original heater was also loose in the original block.

BIG TIP FOR AUSSIES: the recommended procedure is to use alfoil (al-u-min-ium foil) to wrap the element to make it fit snugly. The ‘freshness’ foil (the one you tear out to access the contents) from the top of a Milo tin fits perfectly and makes a great shim.

I have much better temperature control, ie not jumping around as much, with the element snug in the block! This would apply for original blocks as well as my heater was not snug in it either.

– The new mounting block has a built in heatsink. (This is now going to be standard for both the HT and non-HT kits according to new notes on the Flexion website). I DID need two washers under the original nylon spacers to be able to screw the fan down tight.

Step 4b: Install insulation

Not needed, both hot ends came pre-assembled both with insulation. I assume the spacing for the nozzle and barrel are correctly set by Flexion (yes that is correct – pre-set at the factory)

Step 5: Prepare motor

I did not need the extra washers.

Step 7: Install assembly to X-carriage

– Yes, no need for the old heatsink.

Cooling fan looks a bit ungainly with only two screws and at the end of the spacers but the fan is light and it seems to work well. In fact, I wouldn’t be surprised if the block could work without the fan blowing on it, using natural convection!

 

and finally,

Hard to tell which is the HT and which is the ‘normal’ hot end supplied in the kit, the HT is the one with the smooth barrel that clamps to the block. The normal one has an indented surface. Flexion say they will be colour coding the silicone, great idea! (Mine now has a Sharpie ‘H’ on the HT hot end for when I need it)

I have not used the HT option yet. No idea how that performs.

The silicone jacket seems to insulate the heater block much better than the original Kapton tape/cotton.

E-Steps should not change (Flexion recommend 95-96 steps/mm)

The nozzles supplied are not plated, just plain brass, I think MicroSwiss may be bringing out some plated nozzles to suit soon.

I have run PLA and TPU through and it has worked a treat.

I have two rolls of Flexible filaments. One is a roll of the Jaycar stuff and really doesn’t like sticking to my glass, but when it does, it produced good prints. The other roll is Filaform Grey – 90A and it works just like PLA when printing.

++ Like ++  Easy loading and swapping of filament, just reverse the old filament out, advance the new filament in!

Also swapping filament on the fly… I just snipped the filament and fed in the new filament as the print was in progress.

Expensive? Yes. But it works as advertised. Pretty much plug and play with flexible filament and all the other benefits over the standard extruder setup.

I am happy with my purchase after many frustrating hours trying with other solutions, the Flexion works and works well.

Photos follow – anything different in comparison to your printer is probably a mod I have done.

Flexion-3

My “licorice allsort” created by changing filament on the fly.

Flexion-4

The Flexion installed

Flexion-7

The Teflon feed tube. The red wires are from my replacement heater cartridge after the grub screw in the original heater block had seized and the old one couldn’t be removed (WD40 has since fixed that)

Flexion-6

Noctua 40mm fan mounting.

 

3D Printing – using the Cocoon Create (Wanhao i3)

*** Note: some of the info presented here may void your warranty, opening  the control box exposes you to potentially lethal 110/240V connections – please take care and disconnect power before opening the unit. The following are not instructions, just descriptions of my work, I accept no responsibility on how you use his information ***

I don’t know why I bother keeping this site alive. 😛 If you do not understand any of the terms here try Googling them (maybe adding ‘3D’ to the search term).

Well, back in February 2016, I bought a Cocoon Create (http://www.cocooncreate.com.au/) from Aldi here in Australia. Yes Aldi does sell some strange stuff here on occasion.
It is, in fact, a re-branded Wanhao I3, and was a good price at A$499.
This is my first foray into 3D printing, although I have been tempted to have a go for a while. From the start I have been impressed with the quality of the prints from this gadget, I guess my expectations were rather low.

As I have had two of them for nearly a year, I’ll share my thoughts about owning them, pitfalls, urban myths, fun, frustration but thankfully no disillusionment – not yet.

This printer is really suitable for the tinkerer types who are not afraid to pickup a screwdriver and learn a bit. It is not plug and play (mostly) and requires some mechanical skill to deal with running the thing, even in its standard form before you might even consider improving it with mods.

The 3D community… well to paraphrase a Star Wars quote… “3D Printing. You will never find a more wretched hive of scum and villainy”. No that’s not quite true. What is true is the usual clash of amateur learners with (not so) knowledgeable experienced users sprinkled with a few experts (with real engineering understanding).

3D printing covers a few areas of engineering – Mechanical/Electronic (Mechatronic), materials engineering (Plastics and their properties) and a sprinkling of thermodynamics. I’m quite adept at the electronics side of things, had some experience with the mechanics (bearings, stepper motors, etc) but I’m new to thermo-plastics, at least in the formation of objects.

Really simple 3D description: The 3D printer essentially moves a nozzle in 3D space, depositing a stream of plastic to create an object. To do this lot’s of stuff moves and is heated up.

This 3D printer mostly works at a safe voltage (12V DC) for its electronics.

240/110 V comes in through a rear fused receptacle and is fed to a fan cooled switch mode power supply that produces 12 VDC at up to 20 Amps. This DC voltage primarily feeds the controller board (called a Melzi – an Arduino clone) and directly feeds two of the fans, the rear panel fan on the electronics box and the cooling heatsink fan on the hot end. These two fans are always on when the power switch is turned on ate the rear.

The Melzi board is the brains and controls the movement of all things that move – stepper motors for movement – X, Y, Z (2 motors) and the extruder. The Melzi comes pre-programmed with it’s own firmware (although you can re-flash it). It can talk to the outside world in two ways – via files on a micro SD memory card or through a USB serial port.

To print a 3D object, it needs to be ‘sliced’ into layers. Cura is the suggested package for doing this and a great tutorial to get you started on adjusting the settings for Cura in here.

Mods – modifications – here’s were you get your screwdriver fix!

I’ll list the ‘stuff’ I’ve done to my printer (with or without explanation!). Most of this has come from various sources on the internet.

The first thing everyone pretty much agrees on (rare in this hobby) is to print off some dials to replace the wing nuts on the platform levelling screws. I replaced the adjusting nuts with 3mm nyl-loc nuts and the bed adjustment stays pretty stable. Also lock those screws onto the bed with the same type of screws – 3mm ny-loc nuts, this stops them wobbling about.

I added gantry stabilisation (or “Z arm stabilisation”). Use this link from Thingiverse – http://www.thingiverse.com/thing:921948. I profess, I didn’t do any before and after quality measurements but it does make the printer much more stable, especially if you feed your filament from a roll mounted up there. I did not use the full Y Brace bracket either, no particular reason not to.

Fan Noise – Fan Noise – Fan Noise.

Fans are the most intrusive noise from the printer (next to the noise from the Y stepper motor that’s amplified through the platform!). I rate the noise frome the fans as (loudest to quietest): Fan on rear of control box (40mm), internal power supply fan (80mm), hot end (40mm) and extruder fan (30mm). All the fans are 12V.

I have installed a Noctua 40mm fan on the hot end. It runs slower and is designed for quiet operation. I have checked the thermal dissipation with this fan using a Flir thermal camera and it is quite acceptable. I could not see a great difference between this and the stock fan for cooling but the reduced noise was a real benefit.

I have replaced the rear panel of the control box to fit an 80mm fan – see here and added a 100 Ohm, 1 Watt resistor to the fan in the internal switch mode power supply. This again has reduced the fan noise considerably. There was no measurable difference on the Melzi board temperatures after the rear fan change and thermal measurements for the power supply have it running at 29 degrees C with a room temp of 25 after two hours doing a PLA print.

I have not changed the cooling fan for the extruder… yet. Although the fan and duct have been angled more to point at the nozzle now.

If the power supply ever fails, it will be replaced with a quiet PC power supply on standby for the job.

Electronics.

As noted above, I added a resistor to the power supply fan.I have also done the temperature stability mod for the hot end – see here. This does improve the endpoint stability by improving the grounding to the switching MOSFET for the hot-end.

The Vref for the current limits of the stepper motors have been set to 0.684V for X,Y & Z steppers and 0.864V for the E (Extruder) stepper. The extruder stepper motor has a higher current rating. There are a few online guides for setting these, search for “Vref wanhao i3”.

I have also cabled 12V out of the electronics box to the platform area to run overhead 12V LED lighting.

Running the printer.

Initially I was sending files to the printer by loading them onto the micro SD card (supplied with the printer, by the way) on my PC and ‘sneaker net’ them to the printer – this quickly becomes a real pain. Using Octopi,  I have set up a Raspberry PI 2 with a  Microsoft 3000 webcam and WiFi to wirelessly upload objects and to monitor the print process. Here is a good tutorial on how to set it up and if you do use it (it is great!) – then please consider supporting the author.

Filament – so far I have only printed in PLA. I have used the Cocoon filament (blue, green, grey and black), 3D Fuel (Orange and Red), miscellaneous EBay PLA – white, transparent, Bilby glow in the dark, Jaycar wood filament. I have copper and ABS clear to try but I’m wanting to convert the hot end to a Micro-Swiss one first as the ABS runs hotter and the copper/glow/wood might be abrasive.

Repairs and bits…

I have already replaced one of the platform linear bearings. This might be because I used fine machine oil and it *may* to have gelled the grease in the bearings.

Grease – bearings seem to run dry but I think it is the quality of the bearing here. I find a few drops of Singer Machine oil helps if you start getting odd noises when things are moving.

Links:

Google Wanhao GroupGoogle OctoPrint Group