So it’s nearly a year since my last blog post. Where has he been you may ask? Well, after my former 3D printing experiments I felt like I had got the Wanhao Duplicator 4 working rather well. Very well in fact. There was not really much on the technical level I had to add from there. There was, of course, the matter of getting dual extrusion 3D printing working to a reliable standard. Still, with all the various other design projects I have been working on further experimentation was shelved for a long while. Until now.
I want to get dual extrusion printing working well, not so much for the ability to print two-coloured items, but instead, to print in PLA from one extruder and then use a soluble material via the second extruder as a support structure. The reasoning for this is, as you may all be well aware, printing with PLA supports is a tricky business when we get to the post-print stage. Pulling off the support structure can leave rough messy surfaces and also straight out break those more fragile and detailed 3D prints. For complex items with internal area’s that require support, you can’t even get in there to pull out the supports, but you can still see them. My thinking is if I can ‘melt away’ the supports without affecting the PLA all these issues are solved.
So last year I started experimenting with PVA. Great! Non-toxic. Dissolves in water. Sounds simple? I will say this. It caused chaos, mayhem. Okay I exaggerate. It worked at first, but it was messy, and as prewarned to this via the Google forums, it carbonated the hot end. You see me changing the hot end in the last post? Well, that’s why.
I was thereafter recommended by the forums to try using HIPS filament (High Impact Polystyrene.) it dissolves in Lemonene for the same effect. Works better for supports and should not damage the machine.
At the time I did not have a workshop. I did not want to start using anything too chemical/toxic in the house, so I put the idea aside for a while. Then last September I got the workshop space. The idea could be resurrected.
I purchased some HIPS from e-bay. Printing temp recommendation is 230c. I did a dual print. It kind of worked ok, but it was again a bit messy, even after using a purge wall. This was mainly due to the oozing of the currently not printing hot end. It just was not a clean enough result.
So I’m back on Google forums, asking about retract settings etc. to see if I can stop the oozing. I was however recommended to make a hotend hardware upgrade to these:
“…a nickel composite coating designed to be very hard, corrosion resistant, and have good release properties against plastic. It offers one of the lowest coefficient of friction, better then nickel with PTFE codeposit“ so basically with no PTFE tube insert, The idea is that reducing the friction can aid in keeping oozing under control when combined with some setting changes. My 3D printer was also, being the best part of a year down the road of use since the last bunch of fixes, requiring a few new fixes. Again a thermocouple, a fan and also for the first time, a D4 heater cartridge.
So for this blogs technical advice, this is how upgrading the hot ends, and changing the heater cartridge is done…
You have to remove the whole hot end and then preheat the hot end. BE WARNED! Obviously, it gets very hot and you run the risk of burning yourself, keep other flammable items away and use pliers for all of this! Is has to get hot so you can add/remove said components. I found however that heating it to 120/130c is high enough for this.
One issue I found with the hotend upgrades is that they are just 1mm to short to easily get them to the exact height to reach the print bed, and go through the extruder metal bar mount with enough screw end to put the nut back on. You only really get a 1-2mm of thread to do this. I guess you could use a thicker piece of glass on the plate but still its kind of annoying. This meant I have to do the whole process twice!
Changing the heater cartridge involves undoing the tiniest of Allen head bolts on top of the nozzle mount block (and so you have to, in turn, remove/replace the ceramic wraps, and yes, this is what that tiny Allen key that comes with the printer is for. Bet you thought you would never use it!)
I, of course, lost the bloody screw! Ping! Gone! never to be seen again. And so it’s at this stage I must give a shout out the guys at WanhaoUK. They sent me a little bag of free tiny bolts after my mishap. What great guys! If you live in the UK don’t get any replacement parts from anyplace else, trust me, you may get something that does not quite fit. Stick to the originals –
So has all this worked out for the best? Well, I shall let you know! Prints today are coming out well. The only adjustment I made was upping the PLA print temp from 190C up to 200C as the print quality was just a bit off. Must be to do with the new hot ends? They do say each 3D printer has its own uniquely different personality. So note that changing these hot ends does change some on those subtle characteristics of your printer that you may be used to.
Next blog will be about how I’ve been getting along with these upgrade and the results, and hopefully some success with dual extruding.
If you have any tips for good dual extrusion settings I would love to know! Please like and follow 3DWanhao on Facebook and leave a post. Be great to hear from you!
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See you back here soon!