Just came across your online configuration tool. Wow! This makes it a lot easier setting up the printer configuration. Problem is I am on Marlin. Thinking about changing to Repetier firmware.by dave3d - Repetier
I am in the UK. We don't have a Homedepot. I have been looking for one with a relay. I would prefer it to be totally separate to the printer and wire it so it cuts power to the mains plug. I have found a module from China: Put the whole thing in a vented box with a larger mains relay and a mains socket.by dave3d - Safety & Best Practices
brnrd: yes, you are correct. I didn't think of that. A direct short would be the same as overtemp.by dave3d - Safety & Best Practices
Hairspray contains a mixture of butane and propane as the propellant so not good. I don't like the smell of cheap hairspray. Reminds me of old girlfriends.by dave3d - Reprappers
umdpru: you have just given me an idea. Is it possible to pick up a signal from a smoke detector that can be used to shutdown a printer?by dave3d - Safety & Best Practices
An electrical thermal fuse is difficult to implement I think. When I used to run large steam raising boilers, we just ran plastic air tubing across the front of the boiler that held the gas supply valve open. In the event of a fire the tubing melted and closed the gas valve. Simple. Only problem I can see applying the principle to a 3d printer is how to pressurise a thin plastic tube to keepby dave3d - Safety & Best Practices
We need both actually. A few extra lines of code in the firmware sure, but also a hardware safety device to shutdown the printer in the event of a fire.by dave3d - Safety & Best Practices
When I had my near miss and the thermistor pulled out during a print, the temperature obviously dropped below the set point putting full power on the hotend. It got hot enough to melt the peek bit of my jhead and it caused the ball of melted plastic going round with with the head to thermally decompose. There were no flames but clouds of black acrid smoke which filled the living room. Flames woulby dave3d - Safety & Best Practices
Should be back in stock end of Feb ! I got mine as part of a kit from the States. There is a supplier in Hong Kong also.by dave3d - General
I have built an Ord Bot. It is a very flexible design which I have modified quite a bit. It uses Makerslide extrusion, which is used on CNC machines as well. It makes for a neat and rigid design. I don't know why they are not more popular. The rest of the machine uses standard reprap bits. A royalty is paid for the Makerslide to the inventor which maybe why.by dave3d - General
As I understand it, the min temp setting in Marlin for the thermistor is for when it fails completely. It goes open circuit and registers less than 5 deg C. The firmware then shuts down the print. What we are talking about is a situation where the thermistor is pulled out of the hot end but carries on working. This happened with me and nearly caused a fire. The actual hotend temp races away whiby dave3d - Safety & Best Practices
Glass conducts heat too well. The heat from the hotend would be transfered to the x carriage.by dave3d - General
Acetone is not particularly toxic. It is produced naturally in the body after all. It is best to avoid breathing it in though. For me, ABS juice did not work if applied directly on glass. The print didn't just lift in a corner, it completely dislodged even with the glass at 110 deg C. ABS juice works well if it is used on top of Kapton tape, but this is hassle. Elmers glue is easy and cheap tby dave3d - Reprappers
Yes, Ohmarinus. CO2 is the best for an electrical fire. Water is a no no. I think it also needs a device to cut the power. Maybe a fusable link? Got me thinking. A fuseable link secured to the jhead that keeps a mains power relay open? A fire melts the wire and cuts the power. I also think the thermistor should have a failsafe in the firmware to guard against it being dislodged.by dave3d - Safety & Best Practices
I thought about why not just a solid block of ptfe? the same shape as the peek jhead. Must be a reason why not.by dave3d - General
My approach is to speed up the print as much as possible so there are no overnight prints. I have an Ord Bot which is pretty fast anyway but I have Bowdenised it to get it faster. I think if long prints are necessary the way forward is to fully enclose the printer and have an auto shutdown and extinguisher system.by dave3d - Safety & Best Practices
I did not know ptfe went that high. What we want is a material that has low thermal conductivity and high structural strength at high temps. Why not just solid ptfe? I must admit I do not know enough about hotend design.by dave3d - General
Although ceramic, the upper temperature is still limited by the PTFE liner which has a max of 260 deg C. Using PEEK is OK for printing ABS. We need a hot end that can print all plastics regardless of temp.by dave3d - General
I gave up with my QU-BD. Why anyone would make and market something that does not work straight out of the box beats me. I bought the QU-BD MBE extruder. The filament is gripped inbetween the drive gear and a set screw. There is no spring to set the tension. It is very hit or miss trying to set the right amount of grip. Cheap and nasty. I abandoned it and went for a Wade.by dave3d - General
I had a close shave when I first started a few months back. I had not long completed my Ord Bot build and left it doing a print while I went into the garage to do job. The print became detached and the resultant ball of filament pulled out the thermistor! The hot end temperature raced away and it charred the print big style, filling my living room with smoke. SWMBO came running out saying the hoby dave3d - Safety & Best Practices
Floyd: do you apply it when the glass is cold or when it is at 110 C ? I assume one coat?by dave3d - Reprappers
There are quite a few YouTube videos showing how to do hobbed bolts. I think grooved bearings as well. You need to construct a rig I think. Doing it with a Dremel by hand is difficult.by dave3d - General
Ohmarinus: I had bad experiences with a direct drive QU-BD extruder so I went for a bog standard Wade extruder. It is easy to get all the parts. The amount of force a Wade can push on a filamant is very high. Try Ebay or these guys:- They are in Holland. I bought a Wade from them to get me started. I now I print my own bits. The bearings are just skate board bearings. Dirt cheap. I got a grby dave3d - General
I have previously been printing ABS on 6mm glass at 110 deg C covered with Kapton tape and a layer of ABS juice. It has been the most successful method I have found so far. But it is a load of hassle. After reading about Elmers glue on here I decided to give it a go. I have now done about 7 or 8 prints. Not all of them successful. I cleaned the glass first with acetone them polished it with a tby dave3d - Reprappers
The pressure drop of a liquid flowing through a nozzle is proportional to the velocity squared. (Bernoulli's theorem and assuming molten plastic is a Newtonian fluid). The velocity through the nozzle is the same in both cases (as is the downstream pressure) so the upstream pressure in the liquid plastic must also be the same for both 1.75 and 3 mm filament. However to generate the same pressurby dave3d - General
I have had good results with 1.75mm filament and a 0.4mm nozzle printing ABS. I bought two Jheads from hotends.com but unfortunately I have damaged one recently when it overheated and melted the peek bit. They do them in 0.35/0.4/0.5mm sizes. I have two Wade extruders on top of my Ord Bot with short bowden tubes. I went for tried and tested stuff after bad experiences with a QU-BD extruder. I doby dave3d - General
I have recently converted my printer to have a bowden setup. A single extruder at first, now twin extruders. I went for 1.75mm filament from the start and this is quite flexible for use in a bowden tube. Although I haven't tried it, I would think 3mm filament because it is less flexible would be more difficult to use with this setup.by dave3d - General
I need to try out some of the suggestions mentioned on here for myself in due course but so far what has worked for me is:- 6mm thick glass covered with Kapton tape applied in 2" strips (it is cheaper). I use window cleaner spray as mentioned previously. Kapton tape smoothed out with a credit card (visa or mastercard OK). Bed heated to 110 deg C and ABS juice painted on at 110 with small paintby dave3d - General
Great minds think alike.by dave3d - Reprappers
I have bought two Mk V-BV jheads from hotends.com. They are a bit pricey delivered here to the UK at around 50 GBP each. But, after struggling with a QU-BD extruder, the jheads are worth every penny. They just work! I use small fans on the peek bits on mine.by dave3d - General