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Re: Heated bed amps - 10 years ago
Ah... most people put 12V through their heated bed. With only 5V you'll get less than 1/2 the amps and less than 1/4 of the power out of a standard PCB board heater. On the other hand, to get 120W out of a heater at 5V, you'd need 24A, and a resistance of 5V/24A=0.2 Ohms. I don't advise it, but if you want to get experimental, it might be possible to get 100W with what you have, but you shoby DaveX - Reprappers
Re: Heated bed amps - 10 years ago
By ohm's law, 4.37 amps times 1.2 ohms would mean 5.2 volts. Are you seeing 12V across the heatbed terminals?by DaveX - Reprappers
Re: Back half of mk2 heatbed is cool - 10 years ago
Not normal. You likely have a broken trace in the back half.by DaveX - Reprappers
Re: Marlin sometimes does not move motor for small steps - 10 years ago
Seems like it might be a weird rounding problem--there's an awful lot of sqrt(sq()) rounding oportunities in the Delta code. Can you measure the actual movement with a dial indicator? With the 44.4444 steps/mm in your file, it looks like a 0.1mm should be 4.4444 steps per motion. I wonder what you'd see with a 100 steps of 0.01mm.by DaveX - Firmware - mainstream and related support
Re: Trinamic controllers idea - 10 years ago
It doesn't look like it does coordinated motion -- you can "Drive motor 2 to position 1000", but you'd need to externally re-calculate the ramping math to tell motor 1 and motor 3 how to move to make the hotend interpolate between the points in a straight line. Supporting lookahead seems like it would need V_start and V_end, but that doesn't look like it is supported in positioning mode.by DaveX - Developers
Re: how to start print at the center - 10 years ago
It is unclear what you are trying to adjust. You could adjust the center with the physical locations of endstops, the firmware code, the slicer, or maybe the host software. So, if you send: G28 ; to home things M114 ; to see where the printer thinks it is G1 x82 y90 F200; to send it where you think the center is M114 ; to see where the printer thinks it is Does the printer act as expected?by DaveX - General
Re: newbie looking for (wife approved budget) rep-strap machine. - 10 years ago
Try looking at the Bamboo printer in Budget-controller-wise I've been playing with -- The stepper drivers could be re-used in RAMPS, Gen7, or several other electronics (See )by DaveX - Reprappers
Re: G Code genereren - 10 years ago
My comprehension of Dutch is poor. If you are milling based on a set of coordinates, I'd suggest writing a script (in Python or something) that generates the appropriate Gcode cycles. See For filament deposition, you might write a script that generates an OpenSCAD file, which you could process into an STL for slicing into RepRap gcode.by DaveX - Reprappers
Re: i need help 
- 10 years ago
Drill a bigger hole. You can fill the excess space with wraps of aluminum foil. Seeby DaveX - Reprappers
Re: Leds on heatbed - only one lights - 10 years ago
QuoteShaneH Quotetjb1 QuoteDaveX That means you are feeding it DC rather than AC. There are two leds so one or the other will light, no matter which direction you hook up the power. What? Beat me to it...LOL If you were able AC power to feed polarity opposed LEDs connected in parallel, from the MOSFET powering the PCB, both would actually light up. For 50% of the AC cycles, each LED is in thby DaveX - General
Re: Leds on heatbed - only one lights - 10 years ago
QuoteArnold Ok, and meaning of led is just that heatbed is powering ? Yes. If there is a light, there's power to the heatbed. See -- the pic is a little misleading though -- it lights both LEDs and has undersized wires.by DaveX - General
Re: Leds on heatbed - only one lights - 10 years ago
Quotetjb1 QuoteDaveX That means you are feeding it DC rather than AC. There are two leds so one or the other will light, no matter which direction you hook up the power. What? I've got an old plug-in 6.3VAC diode/continuity tester that uses a circuit like that, and the AC lighting both LEDs lighting up was the way that you tell that the Device UnderTest was shorted. You could light up bothby DaveX - General
Re: Leds on heatbed - only one lights - 10 years ago
That means you are feeding it DC rather than AC. There are two leds so one or the other will light, no matter which direction you hook up the power.by DaveX - General
Re: 1.75mm Filament vs 3mm Filament - 10 years ago
QuoteSublime It seems that everyone thinks that 1.75mm takes less force but as far as I understand this is not true. A certain volume of plastic going through a certain size hole at a certain rate takes exactly the same pressure regardless of the filament input size. Or to put it simpler, the nozzle diameter determines the pressure required to extrude not the filament. Its like assuming a hydraby DaveX - General
Re: Heatbed wire - what type - 10 years ago
Soft and hot is a sign it is not OK. Wire size depends on the amps, and how much voltage you want to lose over the length of your circuit. Look up a chart with wire size and amps, like or Some use multiple smaller wires in ribbon cable:by DaveX - General
Re: Wrong bed temperature - 10 years ago
Looks like the PLA came off the bed after a couple layers. Maybe would have suggestions.by DaveX - Reprappers
Re: Mount endstops without brackets(prusa i3) - 10 years ago
You don't absolutely need endstops. You could pick a point on the center of the bed manually and set it to whatever you want it to be. For example, you could setup for 1-paperthickness over the center hole of a heated bed with G92 x100 y100 Z0.1 (See ) and then comment out any G28s in your gcode for printing up some endstop mounts if you want.by DaveX - Reprappers
Re: Anyone trying to implement deadzone PID compensation in Marlin - 10 years ago
You mean or ? I've looked into the deadtime control a bit, but I think that it might be a workaround to problems and defects that don't need to be in RepRap's PID implementations. Deadtime is a common feature in lots of processes successfully managed by PID controllers, but Marlin's M303 Ziegler-Nichols autotune method doesn't recognise or handle large deadtime well. See with Cohen Coon oby DaveX - Firmware - mainstream and related support
Re: Wrong bed temperature - 10 years ago
You might check this bit: // Names for our tables, so you can use them in config.h. // Table numbering starts at 0. #define THERMISTOR_EXTRUDER 1 #define THERMISTOR_BED 0 That names the 10K table for the extruder and the 100K table for the bed, which is the opposite of what your message asks for. Also, that doesn't look like a Teacup table, since the teacup tables map the ADC readingby DaveX - Reprappers
Re: Endstops explantation - 10 years ago
From it looks like hooking + to - is shorting out your power supply and shutting down your system. The + is to supply power for optical endstops. I don't know what your colors mean, or what type of endstops you have, but if blue is the signal, that is what the switch would need to connect to '-' or not. On the RAMPS side , it watches for S to be connected to ground or not.by DaveX - Reprappers
Re: What did i do wrong? - 10 years ago
As Cameron said, it depends on the endstop. See for some different types, and maybe for mechanical endstops and RAMPS, or If everything was fine until you hit the endstop, it sounds like the endstop shorted the +5V directly to ground and overloaded your AMS1117-5.0V until it burned up. That pic doesn't look like the RAMPS 1.4 board here: You could probably take that burned up voltage regby DaveX - General
Re: Best placement for heatbed thermistor? - 10 years ago
QuoteArchelon Thanks for your answer! QuoteDaveX On the Mendel90, Nophead epoxies it to the bottom of the PCB: and then insulates the leads with teflon tubing and high temp tape. Alright, according to the pictures the thermistor is going through the pcb hole. I will use Kaptontape to insulate the wires. QuoteDaveX The thermistor won't melt at bed temperatures, but the wiring and insulation yoby DaveX - Reprappers
Re: Best placement for heatbed thermistor? - 10 years ago
On the Mendel90, Nophead epoxies it to the bottom of the PCB: and then insulates the leads with teflon tubing and high temp tape. The thermistor won't melt at bed temperatures, but the wiring and insulation you choose could behave differently. You want the thermistor thermally connected to the bed so you get a consistent, representative temperature. Loose in the hole may give different readby DaveX - Reprappers
Re: Very large heated bed (400x400mm) - 10 years ago
I'd expect that standard higher voltage heating equipment would have more product testing than special-purpose cheap 12 and 24V stuff, but do be careful with the dangerous higher voltages. Make sure its on a GFCI and treat it carefully. 20A at 24V isn't risk-free either.by DaveX - Reprappers
Re: Need advice on Thermistors - 10 years ago
Yeah, the 1% or 3% are fairly systematic. I think it could affect the beta or the R_25C value, but both should be constant for the same individual part. You could test this yourself by putting the thermistor or hotend in a icewater bath or boiling water bath and measure its resistance at temperatures to see, but I imagine you'd have more variance in keeping your baths consistently stirred versuby DaveX - Reprappers
Re: stl file and first print help - 10 years ago
The bed is typically set at Z=0 with positive going upwards. Depending on how you've set up the z endstop(s) you could be homing at the top of the build envelope or homing at the bottom of the envelope, but I'd think your print should start with z=0 or z=0.5. Are you sure that you are using the z offset right? After homing, try some manual moves and M114 to see if it thinks it is where you tby DaveX - Reprappers
Re: Need advice on Thermistors - 10 years ago
#1: You can use it, but the B=3950 vs B=3974 would read about 2C low around 200C. #2: Your new thermistor is probably a good replacement, since the 1% tolerance is better than the 3% tolerance #3: Use/Make a table that matches your actual thermistor. has an old sample table and a datasheet. Or you could read a couple of those values off of the datasheet and plug them into createTemperby DaveX - Reprappers
Re: Making a huge 3D Printer! - 10 years ago
QuotePulsedMedia When printing small things @ low speed, then it heats up too much, since the high temp is to compensate small melt chamber. Manual adjustments is a bad idea as eventually i want to be running these machines autonomously, i got a ton of things to print, just to begin with when design is finalized, i have about 3500hr printing queue :O Just for the ITX Blades + chassis parts. IMO,by DaveX - Reprappers
Re: HEATED BED - 10 years ago
A hotplate like controlled with a solid state relay capable of 10A or more and some kind of thermocouple sensor setup to reach 500C would be the basic components. Rather than the arduino, you might look into an off-the shelf PID kit like You'd get a better PID algorithm than in most of the reprap firmwares.by DaveX - Developers