Pushwheel temperature mod for Up Plus/Plus 2/Mini I designed this mod to be cheap, simple, easy to assemble and give all the temperature range you could need for your filaments. The mod gives 90° Celsius of variation in 10° steps. I chose 10° because it is about as much discrete variation as you need with an Up printer. Some repraps (open source) 3D Printers need 5° steps especially for PLA but this is due more to some inherent design differences in how fast they respond to heat loss and how much thermal mass they have. All you really need to know is 10° is enough but not too much… on with the build. Parts: The build requires: • 9 x 2.2Ω(Ohm) resistors1 • 9 x 1.5Ω resistors1 • 1 x JST-­‐XH 4pin extension cable2 (or vice versa) 20cm cable. • 1 x Decimal Pushwheel 3 (also called Thumbwheel) 0-­‐9 switch. • Optionally – Temp Mod Case http://www.thingiverse.com/thing:528396 *Purchase Notes: 1. The build actually needs 9 x 3.7Ω(Ohm) resistors but this is not a readily available value so we make these by joining two more commonly available values resistors: a 2.2Ω and a 1.5Ω in series. Should only cost a few dollars. 2. I get these from Hobbyking – just search on JST XH 3S 20cm (a 3S battery cable has 4 pins). You can go shorter but 20cm makes life easier and the extra length makes negligible difference to the resultant temp. You’ll get a back of 10 for $5-­‐6 (AUD/USD/EUR) 3. I get these from eBay. Just search on Decimal Pushwheel. Be careful not to buy the binary ones as these will get you nowhere. Usually you end up with 10 for about $5-­‐6 (AUD/USD/EUR). Here they are laid out: Tools •
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Soldering Iron and solder (the finer the better) Ideally some side-­‐cutters or wire strippers but you can get away with some scissors. A single drop of super glue (cyanoacrylate) Building: 1. Prepare the resistors. Grab one of the 2.2Ω resistors and one of the 1.5Ω and twist one end together. Repeat for all resistors and solder the twisted end. Trim of the twisted end leaving just enough soldered lead to hold together without being too fragile. 2. Prepare and solder the JST connector. In my example I am going to cut the yellow cable about 3cm (1.2inches) from the male connector so it mounts up nicely in my case – you may prefer longer leads on the male end. Your colours may also be different so note the orientation/position of my yellow lead and use whatever lead you have in the same position. One lead will be soldered into the 0 hole and the other into the C hole. It doesn’t matter which goes into which but look at the next photos to see how I fit them up for the case by gluing down the connector. Put them in the two holes closest to the black body of the pushwheel unit like shown. Be wary of a loose wire strand not going through the hole. This will short out and disable the mod – no harm done – just no temperature variation. Optional: If you are using my temp mod case (http://www.thingiverse.com/thing:528396) glue down the connector so it sits in the little notch. You might want to test fit this to the case to make sure the notch it always consistent between switches. I put it here so you can see the intent of the cable layout and connector fitting. Once you have stuck it down it would look like this below though flush against the edge. I’ve cheated here and just used tape to illustrate the final position so it’s not sitting perfectly flush. 3. Fitting the resistors. Fit the resistors so they connect diagonally to each adjacent tab so 0 is connected to 1 via the resistor, 1 to 2, 2 to 3 and 3 to 4. Then we fill the other way -­‐ C connects to 9, 9to8, 8 to 7, 7 to 6 and 6 to 5. Finally we straighten out the last resistor and connect 4 to 5. Before any parts: The plan – our leads (should already be soldered by now) are in yellow. The black shows how each resistor will be fitted. First resistor in – I am going in the C to 9 direction first. It doesn’t matter which way you go but just do one at a time or you’ll find them hard to solder. You can see C and 0 are soldered on the inner edge – that’s the yellow leads we did earlier. Put all the resistors in making sure you arrange them so they pack in as tightly as possible and flush to the board as you solder them (less an issue if you are not using my case). The last one wraps along the outside edge – here they are all soldered in. That’s it once they are all soldered down Just fit it inside the case (resistors sit in the little pocket of the bigger part and slide on the cover (simpler part) on from the back. Alternately you don’t have to use a case at all and can just make the longer lead version like this. Fitting To fit the mod unplug the lead that runs up from your extruder hotend (brass bit with nozzle and 4 wires coming out the side) to the socket on top of the extruder assembly and plug it into the mod instead. The mod then plugs in to the socket from which you just removed that hotend cable. Using the Mod The mod reads in tens of a degree Celcius subtracted from the default temp. That is, 0 give you the default temp for genuine filament. 1 is 10C lower, 2 for 20C lower etc. Each roll of filament may vary in its ideal temp. Even different colours from the same supplier vary. I do a test print with each new roll to find my ideal print temp. I am checking for four things: • Support removal. That raft should come off easy. A test print with at least 3cm radius of raft is a good test. If it’s too hard to remove lower your temp. • Layer bonding. Twist and try to break your print. It should be almost as strong as the genuine filament print. You want to see it break in a similar way to genuine filament prints and not see the layers all separate first. If your layer bonding is weak, raise your temp. • Smell. The Up hotend design does not tend to roast filament when at the right temp. You should have minimal odour from ABS filament. If it’s smelly and particularly smells of burnt plastic when printing ABS the temp is too high, lower it. • Jamming. With ABS, if it jams it is too low (other factors can contribute to PLA jams – see the PP3DP forums). Now this may not happen straight away. Do your test print on fast with maximum infill and make it something solid. This will draw heat out of the hotend fast. If your temp is too low this minor drop before the heater responds and catches up will cause a jam that will probably only be temporary (maybe just a click or two). If it jams/clicks after the first 3 layers raise the temp. I do my test print with Emmett’s Gear Bearing – the ease with which the gears free up is my final test. http://www.thingiverse.com/download:139429 Once I have my ideal temp I write it on the side of the roll so I know what it is in the future. Advanced Use •
You may want to improve print strength for a particular part. Raise the temp one step when the print comes to the part you want stronger but be aware support will get harder to remove. •
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For materials like Laywood you can vary the colour by changing the temperature mid print. Only go hotter than the ideal temp you worked out for the filament. Going lower will risk a jam. Only jump temps gradually, ideally only one step at a time – never more than two inside 30 seconds else the firmware will complain about being undertemp or overtemp and kill the print. You can watch the percentage of nozzle heat if you have Windows and use that as your guide. If you are a Mac user (like me) and don’t get this feedback, just wait 30 seconds or longer between steps. Happy printing.