Show all posts by user
People building or using RepRaps.
Re: Fire safety command? - 11 years ago
Ohmarinus: my thermistor was secured with kapton tape around the hot end. The wires were also secured to the peek bit of the hot end with a cable tie. It did not fall out. It was pulled out. A ball of plastic and a detached print got tangled up with the thermistor wiring as the whole lot went round and round. It then pulled the thermister out with a lot of force.by dave3d - General
Re: Fire safety command? - 11 years ago
There is already a separate post on that: It is for a scenario when full power is on for a certain time but the hot end temp is also dropping. Repetier is thinking about it.by dave3d - General
Re: Yes, 3D printers can go on fire. - 11 years ago
othar, the halon extinguisher from safelinks looks a very interesting possibility. The Amazon one is dry powder.by dave3d - Safety & Best Practices
Re: Yes, 3D printers can go on fire. - 11 years ago
Yvan, my background is the chemical industry. I have never actually seen an automatic CO2 extinguisher system but I have seen dry powder systems. They are single use set off by a glass bulb that breaks at a preset temperature and releases the powder under pressure. The entire contents of the cylinder are discharged. It would be possible I guess to design a system to use a nitrogen bottle particuby dave3d - Safety & Best Practices
Re: Thermistor Failure - Kill Printer - 11 years ago
We need a solution for just one case. It is when the hardware is functioning correctly but the thermistor is pulled out of the hot end. The thermistor temperature suddenly drops and full power is kept on the hot end. This happened to me when a print became detached and the ball of plastic spaghetti going round with the hot end pulled the thermistor out. It charred the plastic and filled my liviby dave3d - Repetier
Re: Thermistor Failure - Kill Printer - 11 years ago
Repetier, can we have a reply to this please. It is important for safety. Can you suggest a couple of lines of code that would catch a thermistor being pulled out.by dave3d - Repetier
Re: Yes, 3D printers can go on fire. - 11 years ago
Having the printer inside an enclosure fitted with a smoke alarm that triggers an automatic CO2 extinguisher system would be ideal. However I cannot find an electrically operated CO2 system that doesn't cost an arm and a leg. Systems used for race cars and boats are also usually powder.by dave3d - Safety & Best Practices
Re: Yes, 3D printers can go on fire. - 11 years ago
Thanks KingRahl. I couldn't have put it better myself.by dave3d - Safety & Best Practices
Re: Yes, 3D printers can go on fire. - 11 years ago
QuoteDeuxVis wrote: I might be dumb, but I don't see the interest in shutting down the power of the printer once it has already catch fire ? Did you read my previous post? I would have thought if you are Admin you had to read everything. To repeat myself, early intervention is the key. Smoke is given off before flames appear and a fire becomes self sustaining. I can think of maybe three ways aby dave3d - Safety & Best Practices
Re: Yes, 3D printers can go on fire. - 11 years ago
Another solution to fire detection I would like to explore is the use of a thermal imaging camera. They are widely used in fixed commercial installations to detect hot spots in warehouses etc. The emergency services also use portable units. It is a well proven method but the fixed systems I have seen have been expensive. I do not know if the cost can be brought down for amateur use. Ideally usby dave3d - Safety & Best Practices
Speed control and estimated completion time - 11 years ago
At the start after the object has been sliced with Slic3r and the print is started, Repetier gives an estimated time to completion which is a very useful guide. If I change the print speed on the LCD panel as I frequently do (I tend to start off slow then speed it up later), unless I am mistaken, the estimated time does not change. I would have thought if I turn it up to 200% then the time to coby dave3d - Repetier
Re: Yes, 3D printers can go on fire. - 11 years ago
Positioning of the thermal fuse will be critical I think. I have had a jhead overheat enough to melt the peek at one end. I don't know what temperature it reached but peek softens at 248 deg C, so it must have been well in excess of that. It was however melted just at one end. The rest of the jhead was unaffected so obviously relatively cool. Because of the low thermal conductivity of peek thereby dave3d - Safety & Best Practices
Re: Yes, 3D printers can go on fire. - 11 years ago
QuoteTOmmm wrote You can get relays that latch, and stay in the 'on' or 'off' state even after the coil has energised or de-energised... such as , datasheet here a double winding latch relay has two coils - one for set, and one for reset. So no matter how many times your smoke alarm goes off or resets, your printer will stay off Thanks. However, I don't wish to change the relay in the smoke alby dave3d - Safety & Best Practices
Re: Yes, 3D printers can go on fire. - 11 years ago
Got my smoke alarm and relay base and wired them up. It is an Aico Ei141 ionisation smoke alarm with an Ei128R relay base unit. Tested it with a bit of burning paper. It cuts the mains power a few seconds after the alarm goes off. However, once the alarm silences and the unit resets, the power comes back on. This is not the action required. It needs to stay off. Only way I can think of doingby dave3d - Safety & Best Practices
Re: Adjusting stepper drivers - 11 years ago
brnrd: just to clarify, is Vref on the A 4988 measured at the pin labelled VMOT or VDD ?by dave3d - General
Re: J-head with ceramic body instead of PEEK - 11 years ago
For what it is worth, I am a retired engineer from the chemical industry. We fabricated parts, bearings, bushes, seals, etc, from filled ptfe for arduous duties. Rulon was one material we used. I think it is a glass filled ptfe. The mechanical strength is far better than solid ptfe and it is easy to machine. There are many grades but Rulon AR for example will withstand 288 deg C.by dave3d - General
Re: Yes, 3D printers can go on fire. - 11 years ago
On the occasion I had when the thermistor was pulled out of my hotend, the print and ball of plastic charred and filled the living room with smoke. I just turned it off at the mains and it stopped right away. It is the first thing to do when electrics are involved. I caught it early on and there were no flames. I did not need to use a fire extinguisher. Since then I have kept a smoke alarm closebby dave3d - Safety & Best Practices
Re: ABS on Glass with abs juice - 11 years ago
I have been using concentrated ABS juice on Kapton tape at 110 deg C. I have just tried dilute ABS juice as suggested. First impressions are it works better.by dave3d - Reprappers
Re: Adjusting stepper drivers - 11 years ago
OK thanks. I will try adjusting them and see if it solves the problem.by dave3d - General
Re: Yes, 3D printers can go on fire. - 11 years ago
LarryJ: it is exactly the same as the Chinese one I posted a link to. I actually ordered it, but it will probably be 4 weeks delivery. I have also bought an Aico Ei141 smoke alarm and base unit that has a 5A relay output. It has nc and no contacts, so it will make wiring easier. Will report back when I wire it up and test it. Smoke alarm is ionisation type. I prefer keeping the smoke alarmby dave3d - Safety & Best Practices
Re: Adjusting stepper drivers - 11 years ago
brnrd: I have also got an Ord Bot Hadron. So I set it on 0.4v presumably under load when it is working? As I said they are nema 17 motors so should be fairly standard.by dave3d - General
Re: hotend assembly problems - 11 years ago
It looks like its from hotends.com. I have got two of them. Maybe a clone though. The resistors supplied with it are 6mm diam. It is cheaper just to buy the right sized resistor I think. Screw the brass nozzle all the way into the peek bit, tighten it (without overdoing it), push the ptfe tube all the way down to the bottom, screw the hex screw in and tighten it down. Finally there is a short piby dave3d - Reprappers
Re: Adjusting stepper drivers - 11 years ago
Sorry, ramps 1.4 and A4988 drivers. So I set Vref to what voltage?by dave3d - General
Adjusting stepper drivers - 11 years ago
I have had a couple of ruined prints recently due to dropped steps. These occurred on the Y axis this time but have occurred on the Z axis in the past. I adjust the stepper drivers by trial and error usually while printing a test cube. They are nema 17 motors. Is there a better way? A more scientific method maybe. I have a clamp on dc ammeter.by dave3d - General
Re: 29 Hours for a single print ? - 11 years ago
There is a serious safety risk if attempting a long print unattended. An option in Repetier is to pause the print part way through (I have done this but not always successfully I must admit). If you pause the print you can lift the Z axis and switch off the hotend and the bed in the manual settings in Repetier. Leave the PC connected. It is then safe. The next day bring the bed and hotend up teby dave3d - General
Re: Printing ABS using Elmers glue on the bed - 11 years ago
Post has been removed that I commented on.by dave3d - Reprappers
Re: Yes, 3D printers can go on fire. - 11 years ago
I have got an Aico smoke alarm on the way with an optional base unit that has a 5 amp relay built in.by dave3d - Safety & Best Practices
Re: Only half of heated bed getting hot - 11 years ago
On mine for 12v you have to link two out of the three of the connections. For 24v you just use two.by dave3d - Reprappers
Re: Yes, 3D printers can go on fire. - 11 years ago
Smoke chains?by dave3d - Safety & Best Practices
Re: Looking for a new filament supplier - whts your experience. - 11 years ago
I have had good experience with ABS filament made by America Instrument - you can buy it on Amazon. All the colours have been good, red, yellow, green so far. For some reason the black ABS is not as good. Edit: sorry just read again and realised you said PLAby dave3d - General