... this forum is more for technologically oriented topics ... https://reprap.org/forum/list.php?424 Mon, 08 Jun 2026 10:48:17 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?424,897058,897058#msg-897058 https://reprap.org/forum/read.php?424,897058,897058#msg-897058 Plan is to combine one of those bearings:
[attachment 121473 bearing8mmM4.jpg][attachment 121474 bearing11mmM4.jpg][attachment 121475 bearing15mmM6.jpg]

with one of those blades:
[attachment 121476 blade8_9mmM4.jpg][attachment 121477 blade12mmM4.jpg][attachment 121478 blade15mmM6.jpg][attachment 121479 blade18mmM6.jpg]

This will also, I think, require DIN980V nuts like this:
[attachment 121472 All_Metal_Locknut_Zinc_Plated_M10.png]

And require some different style part in this style (it is supposed to be cut in 2 half, which will be screwed together,
Also, to fix it to the stepper shaft reliable I am planning to use 20T pulley, similar to what Voron used to do (this is why large hole on back side, it is unfinished yet).
[attachment 121480 HollowExtruderv2.stl]

What do you think?]]> antst Tech-Talk Wed, 19 Nov 2025 03:37:13 -0500 https://reprap.org/forum/read.php?424,896940,896940#msg-896940 https://reprap.org/forum/read.php?424,896940,896940#msg-896940
The printer sounded nasty, and there were distinctly visible printing artifacts.

I re-installed the original acetal rollers, with new ABEC 5 non-flanged bearings (per the original design, but "better"), and all is well.

My supposition is that the aluminum rollers were stiff enough to force the track surfaces in the 80x20 extrusion to yield into compliance, while the original acetal rollers were compliant enough to yield to the track variations.

The devil is in the details.]]> rq3 Tech-Talk Thu, 17 Jul 2025 04:40:33 -0400 https://reprap.org/forum/read.php?424,896700,896700#msg-896700 https://reprap.org/forum/read.php?424,896700,896700#msg-896700
Also a shot of the finished object, a cutter guard.]]> rq3 Tech-Talk Sun, 30 Mar 2025 17:22:13 -0400 https://reprap.org/forum/read.php?424,896359,896359#msg-896359 https://reprap.org/forum/read.php?424,896359,896359#msg-896359 rq3 Tech-Talk Thu, 02 Jan 2025 17:53:35 -0500 https://reprap.org/forum/read.php?424,895862,895862#msg-895862 https://reprap.org/forum/read.php?424,895862,895862#msg-895862
Troubleshooting I have established the following:

• when commanding the hotend to heat, I can read 12V at the hotend connector
• when trying to measure the hotend amps I get a zero reading (ammeter in the heating circuit)
• when reading the hotend amps the voltage reads zero
• the hotend shows a resistance of 5.7 Ohms
• when connected to a 12V lab power supply the hotend heats and draws about 2.5 amps (which could be limited by the power supply)
• when heated with hot air the thermistor shows increasing temp / decreasing resistance
• there's continuity between the RepRap terminals and the hotend connector
• the behaviour is unchanged when swapping the RepRap 1.4 for a RepRap 1.5 (to eliminate a failing MOSFET)

While I do eye a new printer I just don't want to throw away a solid, fully enclosed machine if it can be repaired economically.

Therefore I'd appreciate any hints on what I could have done wrong and/or where else to look before ordering a new machine.


I have three multimeters and a scope at my disposal.]]> slx Tech-Talk Mon, 21 Oct 2024 10:24:52 -0400 https://reprap.org/forum/read.php?424,895508,895508#msg-895508 https://reprap.org/forum/read.php?424,895508,895508#msg-895508
When I set my bed to a setpoint of 70C, this is the temperature stabilization trend. Time = 0 represents when the printer beeps, indicating the bed is fully heated. The temperature is measured with an IR gun in the center.

Time Temperature
0 40
1 52
2 57
4 59
10 61

First of all, there is a 10C offset in programmed temperature and actual temperature. I can compensate for this in the slicer/Gcode, although I would prefer if there were a calibration offset in Marlin (I haven't found on, which is really odd to me). This isn't the biggest problem.

Second, it takes 1 to 2 minutes AFTER the printer beeps, for the bed to fully heat up, and it takes a full 10 minutes for the bed to stabilize temperature.

I suspect both the temperature offset and the delayed stabilization is a result of using the thermistor in the silicon heater, which reads the temperature on the inside of the silicone heater, and not the bed temperature, much less the temperature of the steel sheet. However, this cofiguration seems very popular, especially among Voron-type printers that use a fixed bed...often they use even thicker aluminum beds, like 1/2" thick. Is this a common problem?

One, I could use an external thermistor embedded in the aluminum bed. If I do this, what kind of thermistor do I need to buy?

Two, I could manually adjust the PID values somehow to compensate...such as by reducing the P value to a very low value, maybe it would heat more slowly, so that when it does reach the temperature, the surface temperature will be closer to the thermistor temperature. But I don't know if that would improve the stabilization time, or just take longer to heat up, then I'd still have to wait for it to stabilize.

Three, I could just program in a delay after bed heating, of 1 or two minutes. Marlin has a parameter TEMP_RESIDENCY_TIME which I believe is for this purpose.

Is there something wrong with my hardware setup or is is this typical?]]> PCLoadPLA Tech-Talk Thu, 26 Dec 2024 11:36:55 -0500 https://reprap.org/forum/read.php?424,895387,895387#msg-895387 https://reprap.org/forum/read.php?424,895387,895387#msg-895387
I want to trim about 2mm off one of the edges so it's not hanging off the edge.

On the other hand I could cut a couple 3mm half-circles out of the other side, to clear some screws, then I could shift the whole thing over a couple mm.

I'm not sure if either cutting a couple mm off the edge, or cutting a couple tiny notches off the side will definitely kill the heater or not. I know there must be some kind of conductors that run inside the silicone heater, but what are they? And do they run right next to the edge? And is the whole heater in electrical series, so if I cut 1 wire, the who heater is dead?]]> PCLoadPLA Tech-Talk Thu, 01 Aug 2024 13:19:40 -0400 https://reprap.org/forum/read.php?424,895217,895217#msg-895217 https://reprap.org/forum/read.php?424,895217,895217#msg-895217
When I look at normal stepper motors I noticed they have screws on the "back" as well, and even those screws are sometimes replaced by stand-offs to mount other things.

Is it possible to drill out the front place of a stepper, and run screws all the way through the whole stepper and "sandwich" it to the mounting plate? Then I would not need access to the screws at the front.]]> PCLoadPLA Tech-Talk Fri, 19 Jul 2024 12:23:14 -0400 https://reprap.org/forum/read.php?424,895049,895049#msg-895049 https://reprap.org/forum/read.php?424,895049,895049#msg-895049
The printer is going to have a single umbilical running to the control box and I want to minimize the number of wires, so I don't want to run for example 4 ground wires through my umbilical if I could connect them all together and run 1 ground wire. But it's hard for me to find information about how the electrics are implemented. I'll be using a BTT SKR 1.4 turbo board and Marlin firmware.

I know about electronics and microcontrollers so I know there's multiple ways to setup the pull-up resistors both in hardware on the board, and in firmware by setting the pullups internal to the microcontroller. For things like a part cooling fan, the fan connection on the board will have two wires, labeled - and +. I assume there are two possibilities, either the + is just a straight 24V wire and the ground is connected to ground via PWM, or conversely the - wire is connected to ground and the + wire is connected to 24V via PWM. Either way, I should only have to run 1 wire than run 2 wires.

The 24V heat bed has 2 wires for the heater, but can one of these be connected to ground at the printer, or alternately, can one of them by attached to a general 24V at the printer? How can I find this out with a multimeter etc?

Same with the hotend...can one of the heater wires either be connected to ground or 24V, so I only have to run a single PWM wire back to the control board?

What about thermistors...do I need to run both wires for both thermistors (4 wires total), or is there a way only run 1 wire from each?]]> PCLoadPLA Tech-Talk Tue, 18 Jun 2024 03:38:01 -0400 https://reprap.org/forum/read.php?424,894957,894957#msg-894957 https://reprap.org/forum/read.php?424,894957,894957#msg-894957
I'm having a hard time understanding homing sensors vs. end-stops.

I work for a semiconductor equipment company, and our machines always have a distinction between homing sensors and end-stops. For example, a motion axis will have end-stop switches at each end of travel...these are normally never triggered, they are for "emergency" use, and often they are normally-closed mechanical switches. The purpose of these is to prevent the machine from over-traveling into a space it should never travel to (even with these end-stop switches, usually there's a burly mechanical "just in case" bumper stop as well, to avoid the axis physically smashing the switch and breaking it). There's no need for these to be extremely precise.

Homing switches are different, and are used by the machine to determine the axis position and coordinate system. These are usually optical sensors triggered by flags, so they are precise and never wear out. And there's usually only one of them, typically at one end of the travel, not one at both ends. It's not a problem if these are "triggered" during normal machine operation because the software doesn't necessarily monitor them except when actually homing (it does monitor the endstops).

OK, so my current printer (Sidewinder X1), and most of the 3D printers I see, have a single switch on the Z axis, that triggers with the nozzle somewhere close to the bed. It's used for homing, but it also seems to be used as an end-stop. But that's sort of a problem, because if I set it so that it triggers right when the nozzle hits the bed, then well, the nozzle hits the bed! But if I set it up a little bit, so it triggers with the nozzle like a mm away, then the firmware won't let the nozzle close enough to the bed...except firmwares like Marlin seem to let you actually move the axis PAST the trigger point with babystepping (that's crazy!) by a couple hundred microns or something, but no more, so I guess the idea built into the firmware is that you can have the switch trigger with the nozzle very close to the bed, and then by software adjustment (i.e. M206 "home offset" or M290 "babystep", or M428 "home offset"...but which one???), the firmware can still drive the nozzle a little bit PAST the switch all the way to the bed, but not too far, relying on the ability of the axis to push on the switch some amount past the trigger point without damaging it, which seems like playing with fire, and not much slack there, especially if you are using a mechanical switch with the lever removed.

Using the home offset commands (still not sure which one is the correct one to use) would make sense if you could set the end-stop PAST the maximum axis travel, and use software to set a soft-stop before the end-stop, but if you did that, you could never actually trigger the switch, because the nozzle would hit the bed before it ever hit the switch, so it seems a paradox to place the switch beyond the home position too...

I understand the reason for using 1 switch is because of cost. But if I want to set up a machine PROPERLY...with end-stop switches at both ends of the motion, and a separate homing sensor to establish the software axis position...should I do that? How would you set it up in firmware, and is that type of operation supported at all? Am I just having a gross conceptual failure (GCF) altogether?]]> PCLoadPLA Tech-Talk Fri, 07 Jun 2024 19:57:52 -0400 https://reprap.org/forum/read.php?424,894748,894748#msg-894748 https://reprap.org/forum/read.php?424,894748,894748#msg-894748 blog.reprap.org]

Vik ;v)]]> VikOlliver Tech-Talk Fri, 03 May 2024 10:12:23 -0400 https://reprap.org/forum/read.php?424,894411,894411#msg-894411 https://reprap.org/forum/read.php?424,894411,894411#msg-894411 I'm a physicist based on Santiago, Chile. During my degree I became interested in thin films and solid state technology, and by chance I ended up working with a deposition technique called pulsed laser deposition (PLD).

This may be a bit far fetched, but I was wondering if it may be of interest to someone on the community. Basically I've been working for a while on a variation of the aforementioned technique which may prove useful as a tool for quick prototyping for material deposition and device fabrication/integration. In particular I believe it may become a viable route for the distributed fabrication of integrated circuits and electronics components.

I've begun writing some documentation on the project PLD MM, for anyone interested.

To be brief, the idea is to use a relatively cheap laser engraver to generate a vapor phase out of solid targets in a vacuum or controlled atmosphere. The flow of matter is then modulated by a mask with apertures (stencil or shadow mask lithography) made out of metallic foil to generate a certain geometry over a substrate.

Now the relatively novel part is that the mask(s) are placed on top of a conveyor mechanism which allows the sequential deposition through many different masks. Add the capability to select the material which is ablated by the laser (which is quite trivial) and you could in principle generate complex devices without braking the vacuum or doing any external process to the substrate.
[attachment 120832 PLD_flange.jpg]

I've already generated a proof of concept based on a preexisting PLD system(which unfortunately I've lost access to before being able to generate functioning devices). Here's a small writeup.
Now I was a bit reticent to share that work before mainly because the equipment used wasn't widely available, but the new iteration is completely self funded and I've come to believe that it may possible to make a working machine with a reasonable budget. There are many hurdles and considerations to be taken into account for this kind of projects, I would love to have some input from the community, and will gladly discuss any ideas that may come up.

Best regards, SEU :)]]> seumag Tech-Talk Sun, 03 Mar 2024 08:15:44 -0500 https://reprap.org/forum/read.php?424,893702,893702#msg-893702 https://reprap.org/forum/read.php?424,893702,893702#msg-893702 If you are intrested i will publish a guide to set it up.]]> iskandar69 Tech-Talk Sat, 28 Oct 2023 07:35:54 -0400 https://reprap.org/forum/read.php?424,893682,893682#msg-893682 https://reprap.org/forum/read.php?424,893682,893682#msg-893682
I have BTT SKR 1.4 Turbo and it keeps entering in main menu and buck to Info Screen on its own on my LCD Rep Rap Smart Controller, so I disconnected the EXP 1 on MCU board jack and measured pin 2 and GND on MCU board and I'm reading 1.45 v, any idea tnx ?]]> Vido Tech-Talk Thu, 26 Oct 2023 16:23:48 -0400 https://reprap.org/forum/read.php?424,892772,892772#msg-892772 https://reprap.org/forum/read.php?424,892772,892772#msg-892772 My question is, Why? It is not the use of strain gauges themselves that is my concern: Strain gauges can be stunningly sensitive, fast responding, and mechanically stable for long periods - and they can be cheap as well. My problem is that almost all of the implementations I have seen used very high contact force, often more than 500 grams: Videos on YouTube frequently show detectable vertical movement of the bed when the nozzle contact is made.
I accept that there are added attractions in using a strain gauge between the mechanical extruder and the hotend. This arrangement can measure the back force on the filament, both detecting blocked nozzle conditions and unusual conditions such as hard contact between the print head and the print. Having said that, the more typical design has the combined hotend and extruder hung on a single quarter bridge tongue, an arrangement that adds so much mass that it further limits the slow electronics of the HX711.
I admit also to some bias as I am happy with a single underbed piezo sensor for obtaining the Z reference position and a touch sensor for mesh probing the bed. But even this is not a firmly held belief and the crash of favorite technologies and ideas being kicked off their pedestals often makes my workshop a very noisy place.
I have asked this on this forum, where most of the few remaining denizens are polite. Asking the same on Reddit or the Klipper forum would have my throat ripped out (figuratively) and my body trampled into the dust (figuratively)
So the Why?? remains. Is it perhaps that the Duet Smart Effector and now the Prusa Mk4 have started an avalanche of copycats? Maybe people found the choice of BLTouch, inductive probe, capacitative probe, and nothing else a bit stifling.

Mike]]> leadinglights Tech-Talk Fri, 19 May 2023 04:32:31 -0400 https://reprap.org/forum/read.php?424,892391,892391#msg-892391 https://reprap.org/forum/read.php?424,892391,892391#msg-892391
Currently I am trying to integrate a flow meter into a printed housing. Due to size it will have to be custom made and was considering having the main housing being printed in clear resin and bouncing the optical tach off the blades of the wheel inside.

*** I cant use a hall effect since this will be right next to the pump motor.

Im just wondering if anyone has had any idea if an optical IR or laser diode based sensor can work through the clear resin or if i should design it and then try to seal exposed LED's in the fluid flow.]]> OutcastZeroOne Tech-Talk Thu, 26 Dec 2024 11:39:02 -0500 https://reprap.org/forum/read.php?424,892266,892266#msg-892266 https://reprap.org/forum/read.php?424,892266,892266#msg-892266
My investigations of underbed sensors have convinced me that all underbed sensors are inherently problematic - no matter what type of sensor is used. A method that has proven acceptable may give significant errors with relatively small changes to the bed weight, geometry, or mounting. Even surface contamination of the nozzle or bed surface can result in a hard contact between the nozzle and the bed.

One way of getting around the problems with underbed sensing is to probe only directly above a single underbed sensor which will give the nozzles Z position at contact. In the case of piezoelectric sensors, and perhaps others such as strain gauge sensors, it is also possible to determine if there is plastic or other contamination on the printer nozzle.

Once the Z contact position has been found there is a great deal of latitude in selecting a sensor to perform a mesh calibration so that errors of level or flatness may be corrected or compensated for. Touch sensors such as the BLTouch, inductive, capacitive, and optical sensors could all be used.

I chose to experiment with a touch sensor using a piezoelectric element, mainly because of the extreme sensitivity and usable resolution of the method, but also because I have a stable and reliable interface circuit for the piezo element.

The earliest piezoelectric touch sensor was intended to explore the extent of the errors in a triple underbed sensor and the results were quite disturbing: The difference between the piezoelectric touch sensor and the triple underbed piezo sensor, while mostly better than 10 microns, were as much as 50 microns different in some areas, and could be much worse in other printers.

[attachment 120231 PiezoTouchSensor1.png]

A second piezoelectric touch sensor was fitted to my dual-headed printer which has proven sensitive, accurate, repeatable, and reliable. As it was possible to retract both print heads at once, the touch sensor did not need a mechanism to advance the probe. For most 3D printers though, there needs to be some way of extending the probe.

[attachment 120232 PiezoTouchSensor2.png]

For the third sensor, I tried using a shape memory alloy wire to move a probe into position. The shape memory alloy, in this case, a 0.1mm diameter Nitinol wire, contracts by about 4% of its length when its temperature is raised above 90°C. This touch sensor was not a great success as it was too heavy, despite being constructed from thin metals. It was also too complex and the movement of the probe was jerky and slow. Ultimately it failed as the repeatability was poor.

[attachment 120233 PiezoTouchSensor3.png]

A fourth sensor using mechanical deployment was designed for fitting to a delta printer. The probe itself is mounted on a lever with a fulcrum consisting of a knife edge. When stowed the lever is held in position by a magnet and when deployed it is held against a pressure block on the piezo element. The repeatability of this sensor is exceptional but only after it has been allowed to settle by performing a number of dummy probe operations. Other problems are that it is again too heavy and that the small piezo element limits the lower end of the system frequency response.

[attachment 120234 PiezoTouchSensor4.png]

Possible future ways of building a touch sensor are to use a very light stepper actuator as shown below with a stepper module for scale. The overall size of this is quite tiny, about 18mm at its greatest length and less than 3 grams in weight. While I have yet to characterize these to find out if they are suitable, they are quite inexpensive at £3.50 from eBay.

[attachment 120235 TinyActuator.png]

Another possibility is to make a piezo version of a Klicky probe that can be picked up by the effector to take the bed mesh measurements. This again is in the very early stages of spitballing.

Mike]]> leadinglights Tech-Talk Wed, 20 Sep 2023 11:36:48 -0400 https://reprap.org/forum/read.php?424,892009,892009#msg-892009 https://reprap.org/forum/read.php?424,892009,892009#msg-892009
Both parts were fabricated from the same STEP file.

The stainless steel 3D printed part was an absolute bear to post finish. Machining this stuff is like machining bad cast iron with massive inclusions. Carbide tools would work great, except that they are brittle, and the layers and grain boundaries in the part are guaranteed to break the tool, with no way to easily remove it (carbide is not alum soluable). This part spent 3 days in hot alum solution to remove a broken HS steel drill bit. The Z axis dimension is very accurate (within +/- 0.05mm), but the x and y are unuseable.

It was an interesting experiment that I won't soon try again.]]> rq3 Tech-Talk Mon, 27 Feb 2023 20:34:16 -0500 https://reprap.org/forum/read.php?424,891502,891502#msg-891502 https://reprap.org/forum/read.php?424,891502,891502#msg-891502 www.youtube.com]

Tom has been instrumental in tremendously improving Marlin, particularly as regards fixing very old issues of ADC readings, his introduction and implementation of MPC (Model Prediction Control) for much better control of hot end temperature, and his recent work on movement shaping in Marlin, which can eliminate many printing artifacts.

The take-away from his VDE video is that it is easily made DIY, and that the use of multiple screw threads is pointless, as only one knife edge can be in contact with the filament, as the latest "VDE in action" video shows. I really need to make a new video, but infinite thanks to Tom for his thoughtfullness and efforts!]]> rq3 Tech-Talk Thu, 26 Dec 2024 11:40:41 -0500 https://reprap.org/forum/read.php?424,891410,891410#msg-891410 https://reprap.org/forum/read.php?424,891410,891410#msg-891410 Attached is the reason why, which includes links to Texas Instruments' excellent design spreadsheet, and simulation software. The zipped Gerber files for the board are also attached,
as is a discussion of the amplifier component values.

I often get calls and e-mails from folks confused by the difference between thermistors, thermocouples, and RTD's, and why temperature measurements "bounce" or "suck".

This may help.]]> rq3 Tech-Talk Thu, 26 Dec 2024 11:41:15 -0500 https://reprap.org/forum/read.php?424,891102,891102#msg-891102 https://reprap.org/forum/read.php?424,891102,891102#msg-891102
The smaller the motor, the tighter the tolerances in its manufacture, and I often find that competely opening a motor of a size smaller than NEMA 17 means that, upon re-assembly, the rotation is not smooth. Even the smallest bit of magnetic "dust" within the inner workings, or misalignment of the rotor and stator, within microns, can lead to poor operation.

When it is NOT necessary to completely open the motor, but just to remove its fasteners, I have found it very helpful to apply a drop of Loctite 290, or other wicking thread fastener, to the junction between the iron stator and the aluminum or pot metal end caps of the motor. This locks everything in place, while causing no damage to anything, and still lets the motor fasteners be removed easily if need be.

The Schneckenstruder has been permanently mounted on my go-to delta for well over a year now, and continues to perform very well. Attached is my preferred NEMA 14 version.]]> rq3 Tech-Talk Mon, 21 Nov 2022 18:44:48 -0500 https://reprap.org/forum/read.php?424,891056,891056#msg-891056 https://reprap.org/forum/read.php?424,891056,891056#msg-891056
I would like to modify one of my printers for high temp printing, I dabbled with a v6 clone years ago and found all metal heatbreaks quite troublesome and prone to clogging.
Most likely low quality kit and heat creep, all the fancy modern hotends look as if they have a very short transition between the hot and cold side.
Does this mean that they only work well with short retractions? (1mm or less) I assume if you retract into the cold side you instantly block the hotend?
And so do all metal hotends really need to be direct drive to be reliable?

plus, does anyone have any experience with the Creality E·Fit Extruder?
[www.creality3dparts.com]

Thanks.]]> Plecc Tech-Talk Thu, 26 Dec 2024 11:38:07 -0500 https://reprap.org/forum/read.php?424,890572,890572#msg-890572 https://reprap.org/forum/read.php?424,890572,890572#msg-890572
I having problems with my printer.
Skr pro v1.2 6x tmc2226 REPRAP_DISCOUNT_FULL_GRAPHIC_SMART_CONTROLLER [attachment 119749 Configuration.h] [attachment 119750 Configuration_adv.h]
First it didn't do sensorless homing.
Then i start all over again and now it does homing well but after that nothing seems to work.
Also when i tried to move directly after start up it doesn't move in any direction but when i push home it goes to the home position.
When i put my old bin in again it move okay but without homing.
So my problem is with the new bin it does homing but no movement and with the old bin it moves without homing and prints okay
With the new one it prints without moving.
I already tried 27 different bins I created but with more or less the same result.
Can some one help me? What I'm doing wrong?
Thanks]]> makkeleon Tech-Talk Sat, 01 Oct 2022 08:46:32 -0400 https://reprap.org/forum/read.php?424,890519,890519#msg-890519 https://reprap.org/forum/read.php?424,890519,890519#msg-890519
Today, the entire nozzle blew out of the silver heat block. Even though gold plated, the silver block slowly alloys itself with the tin and copper in the nozzle, until the nozzle threads are gone. The silver heat block is fine, and would likely have worked with a nozzle that was anything but brass.

I'll be trying again with an OFHC copper heat block, also gold plated, but I believe it's important to report failures, as well as what may appear to be to be successes.]]> rq3 Tech-Talk Thu, 22 Sep 2022 12:26:47 -0400 https://reprap.org/forum/read.php?424,890051,890051#msg-890051 https://reprap.org/forum/read.php?424,890051,890051#msg-890051
In any case, the final discussion of the assembly of the vapor chamber heated bed is attached. I used a DS18B20 sensor, lightly coupled with Krytox grease, as a probe, and can confirm that the entire surface is within 0.0625C at 60C. While the DS18B20 may not be wildly accurate in absolute temperature terms, it IS very consistent and sensitive.

For anyone needing a surface that is very consistent in its temperature over a large area, this idea may be of use, you can etch meander heaters into the lower laminate, and remove the upper copper surface completely to reveal a very stiff and flat ceramic loaded material that works very well as a printing surface. It has a glass transition of 285C.

It is imperative that you get all of the air out of the assembly prior to seal off. Also, keep in mind that the entire point of this exercise is that you can apply, say, 500 watts of input to a few square inches of the bottom surface, and expect very consistent spreading of that input to the entire top surface. Almost instantly, like a lid on a boiling pot of water.]]> rq3 Tech-Talk Mon, 25 Jul 2022 18:46:53 -0400 https://reprap.org/forum/read.php?424,889788,889788#msg-889788 https://reprap.org/forum/read.php?424,889788,889788#msg-889788
As far as I can tell, available (or previously available) optical filament sensors have used off-the-shelf interrupted infrared emitters, with phototransistor detectors. Which fails to take into acccount the fact that most polymers, i.e., printer filament, are pretty good infrared transmitters. That filament may look completely opaque to the human eye, even black, but to infrared radiation,
it's as transparent as glass.

For several decades I have sold a commercial product that uses an interesting phenomenon mentioned by E. Forrest Mimms back in the 60's or 70's. Not only is an LED a light emitter, but it can also act as a light detector.

It just so happens that a yellow LED emits light at a wavelength almost perfectly centered on the peak response of a red LED used as a photovoltaic detector. No infrared involved, and if you ADC the resulting photovoltaic voltage from the red LED wth a cheap microprocessor, you have a filament detector that can reliably detect printer filament, of any material or any color, even clear. The clear filaments act as dispersive lenses, reducing the optical input to the detector just as an opaque filament does.

I've tried the prototype with ABS, PLA, PC, PETG, and TPU. In glass clear, red, blue, black, translucent white, gray, and metallic silver. They all worked very well, with a huge signal to noise ratio, not just a few ADC counts.

Attached is a zip file containing the ExpressPCB schematic with BOM, and a brief discussion in Word format.]]> rq3 Tech-Talk Sat, 08 Nov 2025 15:52:47 -0500 https://reprap.org/forum/read.php?424,889464,889464#msg-889464 https://reprap.org/forum/read.php?424,889464,889464#msg-889464
I'm hoping this idea will bring it to within 0.5C across the bed, or better, no matter the energy input (within reason).]]> rq3 Tech-Talk Mon, 25 Jul 2022 18:35:37 -0400 https://reprap.org/forum/read.php?424,889052,889052#msg-889052 https://reprap.org/forum/read.php?424,889052,889052#msg-889052 so I bought a orion precision piezo and tried to install it into my CR10S with a BTT SKR E3 DIP V1.1 but the printer doesn't use it to probe the bed or home.
I made a cable for it that connects to the servo pins on the board like I did with my BLTouch before, but instead of the two extra wires that went to the Z-endstops on the board the piezo board has nothing. I tried to write that into marlin by activating "#define Z_MIN_PROBE_PIN PC14" but it doesnt work. I read on another website that this board has to have something connected to the z-endstop plug but I dont know how to wire it then because It has only three wires instead of the five of from the BLTouch. The probe lights blue if I tap the nozzle like it should. It is just that the printer ignores it when I try to home it.
The manual for this ABL it pretty slim and the community for it is smal so I hope that someone on here can help me.

Here is a link to the current not working Marlin that I try to fix:
[github.com]

I would be very greatfull for a tip if this is a mistake I made with the wirering or the firmware.
Thanks!]]> Kanten Tech-Talk Sat, 09 Apr 2022 19:04:21 -0400 https://reprap.org/forum/read.php?424,888924,888924#msg-888924 https://reprap.org/forum/read.php?424,888924,888924#msg-888924
I'm a visitor from the CNC world (not yet having taken the plunge into 3D printing). I am working on a touch probe for my mill, and I have successfully integrated a Precision Piezo Universal (V2.85). The long thin ruby-tipped probe in the picture is fixed to the center of a 20mm piezo disk in such a way that any contact of the probe flexes the piezo, triggering the sensor. So that's all great!

Here's the issue: the sensor has a 0.25 sec on, active low output. When I probe small holes, the output is sometimes still low when the probe contacts the other side of the hole. That throws an error in my probing gcode (linuxcnc, btw). I could slow the probing motion down, so that it takes longer than 0.25 sec before it triggers again. But I'm wondering if there is any modification that I can make that would instead shorten the trigger time. My understanding is that the quarter second delay was added to make watching the LED blink easier, but what I'd like to do is remove it. Which brings me to my second issue: the sensor circuit.

I'd also like to 're-package' the piezo sensor on a custom pcb that incorporates (among a couple other things) a wireless transmission of the probe signal. (I'm planning on using a microcontroller for this.) I have the V2.85 board, and having the schematic handy would make both the pcb and the delay mod a whole heck of a lot easier! If someone could hook me up with such a schematic, I'd be extremely grateful.

Finally, many thanks to Precision Piezo for all the hard work that goes into the design and construction of the sensor. I'm sure a lot of you have their sensor on your printers, so you know how well it works!

Regards,
Patrick]]> pferrick Tech-Talk Wed, 06 Apr 2022 20:36:59 -0400 https://reprap.org/forum/read.php?424,888570,888570#msg-888570 https://reprap.org/forum/read.php?424,888570,888570#msg-888570
Heat blocks are are as large as they are just to hold the resistive heater.

Thoughts, other than it's a very expensive way to hold a match to a nozzle? Best IR absorbent that will tolerate being threaded for the nozzle, etc., etc?]]> rq3 Tech-Talk Tue, 22 Mar 2022 18:54:08 -0400