Hehe A touch beyond my current means, interesting though nonetheless. $900 dollars for what is a system using cheaper motors than steppers strikes me as a touch steep. The gearing looks pants too, planetary or epicyclic gearing (If you have to have it) is much better. This is why it is chosen for top end precision servomotors. There is a very good argument for over specifying your DC brushedby aka47 - General
Gene Hacker sir I think you may have hit on something there.... I did'nt realise Glycerin soap did the melt like wax thing. This has potential as an extrudeable support medium for cold polymer deposition maybe UV Cure. hmmmmmm I guess the melt like wax thing though would fail using FDM due to the heat of extruded polymer.... cheers aka47by aka47 - Polymer Working Group
Ummm I think I could be missing something here. The arrangement appears to be savagely counterintuitive when you take into account gravity, materials and the center of gravity. The frame, base, etc appears to be light weight aluminum extrusion and the z axis is Granite/Epoxy. In an idealised design:- Surely the heaviest components are better placed lower down (enhanced stability & low cenby aka47 - Casting and Moldmaking Working Group
Ordering from the USA from here in the UK is something of a game of roulette. Sometimes it works, sometimes it doesn't and when it doesn't you have to pay for it again. I wanted some stainless items from Mc Master and Carr. McM & C processed the order, marked the parcel as requested (No commercial value, or you are screwed import tax etc) the parcel duly arrived in an opened and not resealby aka47 - United Kingdom RepRap User Group
Doncaster, South Yorkshire for me. cheers aka47by aka47 - United Kingdom RepRap User Group
And I wondered what to do with all those bio-deisel left overs... aka47by aka47 - Polymer Working Group
Yup agreed Some of the dimensions are a touch out as yet. This is what you get for over designing in your head without parts to play with. The goalposts look wrong. Too tall perhaps. The Pipe-Clamps (Alvin Key clamps are the nearest equivalent with 1" bore pipe) I am using and the steel tube are really for safety handrails etc so are excessively over engineered for FDM, maybe even for CNC but gby aka47 - Shape Deposition Manufacturing Working Group
This is getting a bit freaky. On of the many attractions to CNC milling and FDM the the ability to be able to make molds for anything you like almost at will. I have had a kinky urge to make some Escher style tiles (Flying Books for a library, originally for a house we were buying) for a bit and spent some time reading up on and researching Terrazzo. As a tile material I could use in differingby aka47 - Casting and Moldmaking Working Group
OK Milling and FDM in one machine at the same time. Just been trying to figure out how to put some of this up in the builders blog. Ianus is born (well the prototype is) Ianus is a dual head Cartesian with Independent Z axis on a common X and Common Y platform. Ohhhh sounds clever but not really. Just a gantry style unit with two heads planned one facing forwards and one facing backwards. Tby aka47 - Shape Deposition Manufacturing Working Group
Sebastien Truly wonderous. You have just given me a whole bunch of ideas for bearings & slides. I guess obvious when you have seen it but not until. cheers aka47by aka47 - General
By all means, the thoughts are freeware and made available strictly to GPL hehehehe. For a deliver system I was thinking along the lines of a pressure pot (Like they use for bulk spray painting) with pickup filter in the pot and with the metering orifice and fluid valve on depositing head just prior to needle/nozzle. I don't know if a standard LuLock to tube adapter is available or makable butby aka47 - Polymer Working Group
Is there any mileage do we think in "Post Polymerisation" So far we are largely looking at depositing polymer etc. I rememeber going to see Gunther Von Hagen's Body Worlds exhibition (CorpeWelten). The guy who plastinates dead bodies for anatomy demonstrations. Very clever. Could we deposit an aquous paste (form work). Dry by immersion in acetone (efectively displace all the remaining water frby aka47 - Polymer Working Group
Smoking formaldehyde. Not recommended, apparently Methanol is also toxic due to the way Alcohol Dehydrodgenase breaks it down into formaldehyde. It is apparently the formaldehyde that attacks the optic nerve and is the primary cause of blindness associated with meths drinkers and folk who drink large quantities of home brewed stuff that has a meths content (cider.....). I remember reading thisby aka47 - Polymer Working Group
Clever stuff I had originally suggested LED's because I was envisaging a ring of leds around the deposition type nozzel/needle. The tool head can then Deposit, Deposit & Cure or Cure only and can be selective about which areas get cured and for how long. Whilst a syringe is an option, providing the tubing needles etc were screened to prevent UV penetration a feed line could be used insteadby aka47 - Polymer Working Group
Interesting. Is this perhaps why the choice of 3mm feedstock diameter then ?? aka47by aka47 - Plastic Extruder Working Group
Reading on t'internet The sugestion appears to be that to set the casein you need to mix/spray/pour on formaldehyde. The result is apparently thermo set rather than thermoplastic. Possibly related to Bakelite. Question being can we make a thick paste which has a degree of dimensional stability and dries quickly, extrude it then finalize the set by spraying/misting/soaking in/with formaldehyde.by aka47 - Polymer Working Group
Caesin I have been racking my brain trying to work out where I have come across the stuff in powder form. Now I remember. Body building suppliers provide the stuff in big tubs as a dietary supplement (Increased protein levels) to go in protein shakes etc. (I remember using the stuff once upon a time when I had a brief flirtation with weight lifting and gyms) This should be available in a relatby aka47 - Polymer Working Group
Alternatively One perhaps wonders if there is some mileage in having a thicker barrel drilled out to say 6mm with an insert-able sleeve to reduce the diameter from 6mm to size of the feedstock. The acorn nut would actually cope with what ever liner was used as the hole is central and the shape of the dome end stops whatever diameter is used even up to say 6mm... 5mm might be better drilled thby aka47 - Plastic Extruder Working Group
Zach Yes I think you have a point S-Steel is a pain to work best not, even leaving the acorn nut alone there may be some mileage in the thermal break and cool zone in the barrel route. Nophead An idea, if you need/want it. If you go with a S Steel studding connector, thermal break washer and aluminum cooler barrel. You could make your Brass and Aluminum parts large enough for the larger diamby aka47 - Plastic Extruder Working Group
Guys your observations on alignment have been pretty timely. I have been agonizing over the McWire frame for a short while but couldn't work out what was bothering me. You guys have pretty mush summed it up and that is maintaining alignment whilst under load and being subject to a lot of vibration if milling. (Yes I want to be able to mill things as well) Particularly after seeing the footageby aka47 - Mechanics
The pipe I think you want is Malleable Iron as opposed to steel. The Malleable thing makes it easier to work with. The stuff I was looking at today was available either galvanized or not but didn't come painted black. The ungalvanized is so Grey as to be able to be called black pipe but isn't painted. Umm duno if this is of any value but there you go. Cheers aka47by aka47 - Mechanics
Been musing on High temperature/pressure extrusion. Stainless steel is a not particularly great conductor of heat. Arguably not as good an insulator as PTFE but certainly much better than brass. How about replacing the Brass Acorn Nut with a Stainless steel one (Less heat sinking) Although drilling the stainless one could be painful. Then replacing the PTFE Barrel with an Aluminum one joined tby aka47 - Plastic Extruder Working Group
Most excellent. What are you using for your UV source, are LED's viable ?? (Sorry the questions keep on coming) I was asking re compatibility, because I expected the resin to have some form of thinner or solvent as part of the mix. I spent some time once doing some GRP work during the summer break, styrene monomer is the main thinner in the resin. We also used acetone to clean the tools at theby aka47 - Polymer Working Group
Bet you could get even better than 0.1 of a degree if you added a vernier scale. Grin Anyone seen the vernier clock someone made on t'internet. Cool toys. aka47by aka47 - Mechanics
Fernando Sorry for this another quick question. For depositing the resin it should be possible to use a motor driven syringe and standard deposition needles. What is the compatability like between the resin and standard syringe type plastics, ie will the uncured resin react with/dissolve or ugger up a standard plastic type syringe ?? Cheers aka47by aka47 - Polymer Working Group
Looking at the McWire. A quantity of slop under load could potentially be removed by by replacing the spring tensioning with something somewhat stiffer. For example mount one bearing using a central fixing and one opposite with an off center fixing (Think Cam) but close enough to rotate the bearing against the slide (removing slop) before tightening the fixing and clamping it in position. Altby aka47 - Mechanics
Thoughts Instead of using a large chunk of insulator what about using a much thinner thermal break made out of something less plastic like. Followed immediately by an aluminum barrel with turned fins on it to act as a heat sink. The figures I have seen for PTFE seem to indicate around 260 Deg C ish, 300 and more is getting awfully close to the temp it will be in it's most runny (although not muby aka47 - Plastic Extruder Working Group
Axminster should be able to either give you the information you need or point you at the manufacturer for it before you buy. Most capable manufacturers these days leave PDF copies of their manuals etc on line. Last I saw digital calipers and micrometers being used hooked up it was when I spent a short time making Break Linings with Ferodo at Chapel-en-le-frith the in the peaks. They had them hoby aka47 - Mechanics
Unfortunately neither is any more or less accurate than the other. It is all Dependant upon your end use matching your specification matching in turn your design and your constructive accuracy/Precision. Pick which you fancy, make sure you understand the ups and downs (Pun intended) then the do the best you can with accuracy/precision within the budget you have to work with. Personally speakinby aka47 - Mechanics
Aha all is explained. That sounds sensible to me, I thought there may be some clever polymer/physical science behind the choice. But there is even cleverer fiscal science at play. Grin The notes and experiments on extruding polymer chip are interesting. I think this one will take a clever bit of lathe work to get the differing diameters into the extrusion screw (Compresing/Feed, Degassing, Meteby aka47 - Plastic Extruder Working Group