[Master of nun]

Hi Guy's,

It's a rare thing me venturing this far down the forum pages....I generaly hide out in the DIY router area.

Anyhow, I'm very interested in your experiences/ideas surrounding the idea of either adapting my current machine or a stand alone machine for 3d printing parts typically 2200 x 400 x 200.

printing media would ideally be blue machinable wax as I have a ton of it.....yes literaly 1000kg, some $15000 AUS. It has a softening temp around 8o deg celcius and a reccomended recycling temp to pour of around 140 deg. celcius.

I see there has been a little movement with using 3d printing with concrete on a very large scale in constuction so I guess I'm not completly mad.

I imagine i'll need to print onto a heated platten ( if I print using a heated product such as wax), experiment with nozzle temps of 100-125 deg. celcius.

if I use my slow router I'll probably use a nozzel diameter of 5mm to create rough stock and remachine with the router after the wax has cooled, however if I were to build a quick "traditional" printer with belt drive etc. I could go for a small nozzle and have a product that has a much better finish to begin with.

I'm producing one off model ship moulds for fibreglassing, sometimes it's the plug to take the mould from......depends on the hull shape.





Software

What is currently the preferred cheap/opensource software at the moment?
Would ReplicatorG be your recommendation?



Heated Nozzle and drive options

Do you have any ideas on how to feed a pelletized wax into the heated nozzle?









I would love to hear(read) your suggestions!



Cheers Liam

[awerby]

I don't think this is really going to work too well, Liam. While machinable wax is great material for carving with a CNC machine, it wasn't formulated for hot deposition. To get an accurate print, you need a material that stays where you put it - that wax, when melted, just runs everywhere. Its other problem is a very high shrinkage rate, which means it will pop off your platen as soon as it cools. A heated bed isn't going to help with that; it seems that it will either melt the wax, so it slides around on the platen, or it won't be hot enough to make any difference. Unfortunately, machinable wax has a rather abrupt setting curve - it's either melted or solid; there's little in between. You'd ideally want something stickier, that shrinks a lot less. Save your ton of blue wax for something it's good for.

So the first thing you'd need to do is formulate a wax for this application. Or look into Matt wax - it's made for extruding out of a hot gun. There have been hot wax 3d printers invented - look up the Sanders (later Solidscape) machines. These have been used in the jewelry industry for a long time (as these things go). They feature a planer blade that levels off each layer of wax before the next is laid down; this is important, because the surface tension of the wax makes an irregular rounded top contour that otherwise would shed the next layer off in one direction or another.

If you're going to machine it anyway, I don't see the point of printing it first. The only justification for 3d printing is to get configurations that you can't get with regular CNC. Something relatively simple like a hull plug doesn't seem like something you'd need this for. It seems like building a tilting axis for your spindle would be a more productive use of your time, if this is what you're making. But if you do want to build a wax printer, you need heated hoppers for the wax, heated flexible lines to get the wax to the nozzles, and heated nozzles - but all this has to go into a cooled box, so the wax doesn't just sit there as a puddle.

Andrew Werby
www.computersculpture.com

[Master of nun]

Hi Andrew,
Thanks for taking the time, you've made some great points there...I hadn't thought of the shrinkage rate too much and though if I tried extruding at a lower temp there would be less of it, but as you say, this wax does turn to liquid fairly abruptly. Matt wax looks good, but my guess hidiously expensive.

I guess I'm just trying to avoid having to build my wax recycling system and the post curing oven.....I've been told I may have to slowly bring the temp down upto over a week with the size blocks I'd be casting.

Your right......the 4th axis should be considered first to minimize tooling length for the machinable wax.

Always good to bounce a few ideas around with someone....


Cheers