Anycubic Kossel Linear Plus (3d printer) bed leveling sensor

  • SpinRite v6.1 Release #3
    Guest:
    The 3rd release of SpinRite v6.1 is published and may be obtained by all SpinRite v6.0 owners at the SpinRite v6.1 Pre-Release page. (SpinRite will shortly be officially updated to v6.1 so this page will be renamed.) The primary new feature, and the reason for this release, was the discovery of memory problems in some systems that were affecting SpinRite's operation. So SpinRite now incorporates a built-in test of the system's memory. For the full story, please see this page in the "Pre-Release Announcements & Feedback" forum.
    /Steve.
  • Be sure to checkout “Tips & Tricks”
    Dear Guest Visitor → Once you register and log-in please checkout the “Tips & Tricks” page for some very handy tips!

    /Steve.
  • BootAble – FreeDOS boot testing freeware

    To obtain direct, low-level access to a system's mass storage drives, SpinRite runs under a GRC-customized version of FreeDOS which has been modified to add compatibility with all file systems. In order to run SpinRite it must first be possible to boot FreeDOS.

    GRC's “BootAble” freeware allows anyone to easily create BIOS-bootable media in order to workout and confirm the details of getting a machine to boot FreeDOS through a BIOS. Once the means of doing that has been determined, the media created by SpinRite can be booted and run in the same way.

    The participants here, who have taken the time to share their knowledge and experience, their successes and some frustrations with booting their computers into FreeDOS, have created a valuable knowledgebase which will benefit everyone who follows.

    You may click on the image to the right to obtain your own copy of BootAble. Then use the knowledge and experience documented here to boot your computer(s) into FreeDOS. And please do not hesitate to ask questions – nowhere else can better answers be found.

    (You may permanently close this reminder with the 'X' in the upper right.)

rfrazier

Well-known member
Sep 30, 2020
566
194
Hi all. Got a 3d printer question. Thought I'd check with the hive mind here before going on to a bigger 3d printer forum. I have an Anycubic Linear Plus delta style 3d printer from a few years ago. It has a removable probe switch that I can use to do automatic bed leveling. I want to permanently attach a different sensor that stays there all the time like a bl touch or an inductive or an infrared sensor. I've been YouTubing and Googling extensively for hours and hours trying to find out how to do this. If anyone has any specific ideas or experience please let me know. Info on the existing detachable sensor won't help. I specifically want the sensor to always be there so I can bed level before every print if I choose. The printer has a trigorilla board but I don't know the version number at this moment. Let me know what you think. All help is appreciated.

May your bits be stable and your interfaces be fast. :cool: Ron
 
I took a quick look to see what the printer looked like. I don't know how feasible this would be but it was the first thing that came to mind. As you mentioned, an IR sensor. By aiming the beam at the bed but at an angle, the intensity of the beam on a sensor would vary depending on distance between the emitter and bed. Of cause an analog reading from the sensor, maybe a DVM would be needed to read the output. I am not sure how practical or sensitive such a setup would be, perhaps a low power laser diode in a similar setup would work better. For a more 'way out' idea you could use a laser with a mirror placed on the bed and reflect the beam off at a distance for more accuracy. Obviously this would not be an automatic method and a few spots on the bed would need to be checked.

I assume you have seen test prints, maybe on Thingiverse that printed small thin squares at multiple places on the bed to check for level. My printer has nowhere near the height ability of yours so I can see where bed level can be a big issue.

Just an idea, not sure if it can be used.
 
  • Like
Reactions: rfrazier
I was curious and decided to ask 'The old man in the cave'. Attached is the 'chat' file.
 

Attachments

  • chat L level.txt
    24 KB · Views: 156
  • Like
Reactions: rfrazier
@Ralph Thank you for all that info you provided including the Chat GPT. Even though I brought up the AI topic in the other thread here, I'm continually amazed at what the bot can produce. I hadn't checked with it yet for this topic. I read through the transcript of your chat. Sometimes I feel like the bot is a politician, giving general and nebulous responses. But, realistically, with 3D printers, there's lots of "it depends" because there's so many people producing things at the hobbyist level and little standardization. So, I understand some ambiguity in the responses. Also, if I'm honest, it would be hard to get a better response from a human. Most of what the bot said was right on target, even if vague, including the oddball nature of the kinematics (geometry and construction) of a delta printer and including some of the specific characteristics of the Anycubic Linear Plus. I'm quite impressed actually. PS for anyone here who has an interest in 3D printers but not familiarity, delta printers are one of the strangest and most mesmerizing things to watch, for me at least. YouTube delta 3d printer time lapse operation. (Edit: changed the words time lapse to operation because time lapse videos often don't show the operation of the printer as each frame of the time lapse video is often taken when the print head is in the same position.) After supper here in my time zone, I hope to elaborate a little more on my problem. @Ralph it looks like you've had lots of conversations with the bot based on your chat history (in the file you provided). And, I must say, you're getting pretty good at generating queries. Some of the bot's responses pointed out some (embarrassing) deficiencies in my language or lack of specificity of my original query here on the forum. For future reference, below is a diagram of how these printers work.

cartesian-vs-delta.jpg


May your bits be stable and your interfaces be fast. :cool: Ron
 
Last edited:
I thought I'd add a few more details. For those of you not interested, just ignore the thread. Others may find it interesting though. And, some of the discussion might be useful for other electronics projects. Learning how a printer controller works is an interesting, if frustrating, experience. Also, I welcome and appreciate all input even if someone doesn't have enormously detailed answers.

A cartesian printer works with 3 axes at right angles, X, Y, Z. There are various combinations of whether the print head or the bed moves in what direction. X is left to right facing the printer, analogous to the width of a box. Y is the in toward the printer or back toward the viewer direction, analogous to the depth of a box. Z is the vertical direction, analogous to the height of a box. Two general procedures are relevant to 3d printers. One is calibration and the other is bed leveling. For a cartesian printer, calibration mainly assures that the axes are actually perpendicular and controlling how much each motor moves and how much filament is extruded. Bed leveling makes sure the bed is as level and as flat as possible and parallel to the motion of the print head. In many cases, the print bed is mounted on springs or silicone pads and has adjustment knobs which allow each corner to be raised or lowered manually. You get the bed as level as you can manually. Then, automatic bed leveling can be used with a sensor switch that is lowered to the bed one point at a time and the firmware notes the difference between the actual zero vertical position and the theoretical zero vertical position. The firmware then adds this delta into the equations while printing to make the print head track the bed even if the bed is warped or not entirely level and perpendicular to the motion of the print head. Much of what the Chat GPT that @Ralph mentioned talked about referred to a cartesian printer.

A delta printer is a different, and in my opinion, somewhat ingenious contraption. The delta printer has a triangular base and top and a round print bed. The bed doesn't move at all. Each corner of the triangle base has a vertical tower going from the base up to the top plate. On each column, moving mounting points travel up and down each tower. Control arms run from those mounting points down and toward the center to the print head. By moving the mount points on the towers up and down, and doing all sorts of gnarly spherical trigonometry calculations, the printer head can be moved to any point within a cylindrical print volume. On on a printer of this type, calibration involves determining the printer radius, height, control rod length, AND determining the angle of the vertical towers, among other things. Theoretically, the towers are vertical and perpendicular to the base. In reality, especially with a DIY assembly, they can be a few fractions of a degree off. Any variation can throw the calculations off as well as the print head position. For reference, it is generally desired to position the print head to a vertical point within .1 mm, or the thickness of a piece of paper. Getting it wrong can crash the print head into the print bed and break or damage things.

Because the bed doesn't move, adjustments are mainly done by entering numbers on the control panel or via computer connection to the printer, changing the various geometrical parameters. The printer firmware has routines to probe the bed with a sensor on a grid of points. It reverse engineers that data to determine the key geometrical parameters of the machine. My printer has a removable magnetically attached sensor which is a microswitch. I can attach that and do automatic calibration or bed leveling. Then I must detach the microswitch. Now, granted, the parameters of this kind of printer don't change much. But, many cartesian printers have a sensor attached at all times, and they can do a bed leveling at any time, even before each print if desired. That's what I'm trying to do, to get the sensor to remain there all the time and automatically work when needed. It cannot be the original sensor, because that mounts below the extruder nozzle and obstructs it.

If the sensor is mechanical, like the microswitch, or a moving pin or arm, it must deploy and then retract. Otherwise, the mechanical part of the sensor may crash into the print that's being produced. If the sensor is non mechanical, it can remain fixed at all times. Major options for those are inductive, which triggers near metal but doesn't work on glass, capacitive which triggers near most things but varies with humidity, ultrasonic which is not common, and IR (infrared) (as @Ralph mentioned).

I found this (IR) sensor that looks very cool. I'll also admit that, buried in all the text in these links, the solution to my problem may exist. This sensor uses modulated IR light to reduce false triggers.




So, I fundamentally have four problems. First is getting a sensor from Australia. Hopefully that won't be a super problem. Second is mounting the unit. Again, hopefully, not too complicated. Third is connecting the sensor to the controller. That may be somewhat of a problem since all these electronic interfaces aren't standardized. Fourth, is altering the firmware to respond properly to an always attached sensor versus a sometimes attached sensor. My printer is running Marlin 1.1.9 and they have documentation for that, as it turns out.

So, that's where I am at the moment. I probably have to slog through all the docs, but I figured if some of y'all have advice, I'm certainly willing to look at it. 😁

May your bits be stable and your interfaces be fast. :cool: Ron
 
Beware of IR sensors, as they often will give a small error with surface variation, like colour and scratches.
 
  • Like
Reactions: rfrazier
Wow, your printer sounds far more complex than my Quidi. I've told people with a little interest in 3D about the number of settings and combinations of them which is staggering, and obviously more so on your printer. Glad some of that info gave you a few ideas. When I used to work on check sorters there were many IR sensors along the tracks to monitor check position and determine if there was a jam. Most of the sensors had a triangular shape with the emitter and detector aimed at an angle toward each other so that the beam would bounce back and be aimed into the detector. The critical one was right before the read/ write head since it triggered timing to actually read the encoding. It used 2 sensors, one that shined through the track with a separate detector on the opposite side, and one of the triangular configuration set at different heights to allow for possible physical damage on the leading edge of the check. That was a pretty complex machine in it's day both mechanically and electronically. It was a Burroughs B9134 if anyone is curious enough.

Oddly enough I became better at putting questions to AI after watching the movie Colossus- The Forbin Project (thanks @Barry for giving me the link to watch it some time ago). For some reason that movie pops up in my mind as I write questions, often going back to re-word before entering. Before that I would often get 'in trouble' when texting and what was understood at the other end was not what I meant.

When you get up to the firmware part try giving ChatGPT a crack at it.
 
  • Like
Reactions: rfrazier
Beware of IR sensors

@SeanBZA That is an interesting point. I'm sort of waffling on the IR sensor for that reason. I don't want the sensor
to fail to read and crash the print head into the print bed. Even when the sensors work, there's only about a 2 mm range for error as I understand it. I've ordered a magnetic sticker substrate and flexible steel bed surface coated on one side with textured PEI and smooth PET on the other. I'm going to put all that on a piece of glass I already have. I still would like to get a sensor of some sort. Everything has complications. I may go with an inductive sensor, which should work with the core of the steel bed surface. But, then, if I wanted to go back to plain glass, it probably wouldn't.

Oddly enough I became better at putting questions to AI

@Ralph When I was using Chat GPT to generate text for a children's book described in the AI thread here, I discovered that you have to be very precise unless you just want the bot to use its own "discretion". Sometimes free flowing responses are good, sometimes not. But, making this up, if you want a scene with a young woman in a blue dress digging for a mythical artifact by a river with a pickaxe, assuming those details matter, you have to say that. The more precise you are, the better the results. That also applies to AI image generation. If you go on to an image generation site like https://app.leonardo.ai/community-feed you'll find some amazing (and some strange) images. Sometimes the prompts used for those are a whole paragraph long. Precise language has become a lost art in this era of short attention spans and communication systems like texting which encourage destructively abbreviating our language. The difficulty thumb typing on a phone doesn't help either.

May your bits be stable and your interfaces be fast. :cool: Ron
 
The problem I developed from texting was to read the message too quickly, sometimes missing important things, and replying too fast without thinking how my reply might be understood. To the point you made, by coincidence I was reading an edited Chat I'll probably post soon. I happened to glance over at a TV and there was one of those court case/ mysteries on. It came to me that lawyers, at least good ones, are probably schooled in the precise use of words for the same reasons they matter with AI- but with real world consequences in the case of lawyers.

While I use AI to learn some things I find it at least, maybe more interesting to probe how it 'thinks'. I rarely log into AI with more than a vague idea of what we will 'talk' about, sometimes no idea at all. Most of the time I question it depending on what it has replied and whatever pops to mind based on that. I do throw it 'curve balls' from time to time just to see how it responds. I find it interesting.
 
  • Like
Reactions: rfrazier
I have been looking at 3d printers for a while, so have no experience. However, I rather the head moves since it should reduce the error (less inertia). Most printers are cartesian, and would imagine it has to do with how we see the world. However, could a delta movement lead to harmonics if the speed is too fast?

Also seems that feedback is important since too many things can go wrong while printing. One I have been eyeing and hoping it become more affordable is the bamboo printers (https://bambulab.com/en/p1), and Ron they have an Australian store
 
  • Like
Reactions: rfrazier
That Bambu looks like it might be interesting. I didn't read everything on the site, but one thing that jumped out was it's speed. When asked I've told people the biggest consumable of 3D was time to print. If you haven't already do a lot of research and read current reviews. When I first decided to buy a 3D I knew next to nothing about them except for the limit I wanted to spend. Much research later I bought a Quidi X-Plus. From reading it is far from the most popular but just about everything written about it is good. The other deciding factor was the large number of filament types it could print- although to date I've only printed PLA and PETG.

After quite a bit of use perhaps the thing I've noticed is the print bed size. While mine is reasonably big, mostly from wanting to print clocks I've found my print bed to be too small, so that is something to take into account when buying. A couple times I've scaled down the print size to fit the bed which let me print the clock, but the battery movements could not be scaled down to match :) My original thought was to print a mechanical clock but I haven't tried that yet.

I've found that USUALLY if the first layer or two printed OK the rest of the print was OK, so I generally keep an eye on it for that long, and if it's a large object I take a few random checks along the way. Aside from PLA and PETG, if printing other type filaments you will probably want some kind of venting for fumes. A good steady base to put the printer on will also be a plus. I am sure others on here with more experience on 3D can offer some tips.
 
I have been looking at 3d printers for a while

Ron they have an Australian store

It's too hot and humid outside for me to 3D print inside. I'll explain that later.

I have a few thoughts which may or may not be useful. Here they are for what they're worth. I have years of experience TRYING to get my two 3D printers working. And they never have been working to any substantial degree. @Ralph has likely done more printing than me. Here's a summary of my sad tale. YouTube channels / people Maker's Muse, Tom Sanladerer (apologies if spelled wrong), 3D Printing Professor, Chris Riley, and Teaching Tech as well as others give good information.

This is important. There are two basic types of 3D printer enthusiasts with many shades of gray in between.

On one side is someone who want's plug and play. They want part production and little tinkering. They just want it to work and not to be working on the printer. They want reliability and dependability. The PRINTED PART is the project. For these people, this usually means more expensive and more proprietary corporate printer vendors with potentially better parts, maintenance, and support. Note that expensive and proprietary doesn't necessarily mean easy use and reliability and good support though.

On the other side is the tinkerer. They mainly want to build the printer, adjust the printer, experiment with the printer, upgrade the printer. Of course they want reliability and dependability where they can get it. But, the PRINTER is the project. For these people, this usually means more DIY or partial assembly, more grass roots, more community based, more open source, less expensive AT FIRST machines. It may mean less or no corporate support, less available parts, and more self repair, self upgrade, and tinkering. These machines CAN be reliable right out of the box, but the dirt cheap Chinese ones usually aren't. Maker's Muse YouTuber says we're starting to get out of the race to the bottom we were in since about 2017.

I gravitate toward the just want it to work camp but am between the center and the side of the scale. I CAN work on the printer as I have an Electronics Engineering Technology degree and a technical mind and background. BUT, I have ended up working ON these machines much more than I wanted for years and they're still not working.

Around 2017 ish, I bought an Anet A8 (not the A8 Plus). It seemed like a bargain at $ 150 or so. NOTE, I've spent several TIMES that on this printer afterwards. This printer is famous for, unfortunately, starting house fires. I studied it extensively and pre purchased many upgrade parts, some of which I've never installed. Right off the bat, I bought, better drive belts, lock washers and flat washers, drive belt pulleys, linear bearings, power supply, mosfets (helps drive the heaters without burning down the house), power cabling, bowden tube conversion (moves extruder motor off of print head, pros and cons), and a few other things. I bought a glass plate for the bed, which was warped. I bought a thicker and expensive custom glass plate. I bought a PEI sheet to stick to the glass. I did eventually get it working well enough to print a mounting bracket to put on a better clone extruder. I printed with PETG and it welded itself to the PEI sheet ruining the bed. I also immediately updated the outdated firmware to get the fire protection working that should have been there anyway. I soldered the heater wires to the print bed and removed the lame connector, which also is known to start fires. All these changes and upgrades were a major hassle and time sink.

Here's why I can't print inside when it's hot and humid outside (or cold). 3D printers produce pollution in the form of microfine particles smaller than a HEPA filter as well as (sometimes toxic) odors which can be a health hazard. If I run a ventilation system (which I should, plus and enclosure) which expels air from the house, I have to intake air into the the house to replace whatever air was expelled. At the moment, that means hot and humid air which I don't want.

@a viewer Thanks for the tip but I'm in GA in the USA, not Australia. :)

Gonna take a supper break and come back and type part two of this story.

May your bits be stable and your interfaces be fast. :cool: Ron
 
Last edited:
OK, part 2 of my printer saga.

A word about printer bed surfaces. Both of these printers came with just an aluminum surface, which is NOT totally flat. They recommended putting hair spray, glue stick, or painter's tape on the bed to make the part stick. I, HOWEVER, am of the belief that I shouldn't have to put ANYTHING on the bed to make parts stick. So, I've tried PEI sheets, which work well for PLA and too well for PETG. I've tried ultrabase glass beds with a ceramic coating. I've tried Build Tak clone stickers. No offence to any one else who uses these successfully. But, for my next mod, I'm going with a flexible removable magnetic surface on top of thick glass with Textured PEI on one side and smooth PET on the other side (similar to carbon fiber).

At around this point the extruder heater cable broke on my Anet A8. And, I found out about delta printers. And, I bought the Anycubic Kossel hoping it would be more plug and play. It also came with outdated firmware, which I replaced. I then had to recalibrate and had difficulties with that. At one point the print head jammed into the bed and gouged it. I have occasionally got it to work well enough to run test prints. At some point in this time frame, I started printing with PETG which can be used at higher temperatures than PLA. (I mentioned toxicity earlier. ABS emits toxic fumes, FYI.) I started getting parts off the printer which I could easily crush in my hand. PETG parts should be very strong.

This lead to a whole other area of knowledge gathering on ... HUMIDITY. Lo and behold and who would have guessed, but PETG likes to suck up water from the air like a sponge. In some very bad examples, you can see steam coming off the extruder. Guess what, when your filament is humid, assuming it doesn't break in the printer, your printed parts lose their structural integrity. AAARGH!! Then I got a food dehydrator and sabotaged it for filament. Then I got an individual filament dehydrator which I've had little chance to use.

So, here I am today. The Anet A8 needs new extruder heater, new firmware, new calibration, and a new build surface. The Anycubic Kossel needs new firmware, new calibration (hence the thread on sensors), and a new build surface. Either or both printers, if I'm using both, need an enclosure and a ventilation system with a big vent hose going to the nearest window, only usable on fair weather days. I still need to get the procedures and operation of the filament humidity control system working.

There are no doubt many ways to do things better. But, that's where I am 6 years later. If I were to start over, here's what I would look for. There are many ways to build printers. These are just my opinions.

I don't like bed slingers that move the bed extensively. No offense to anyone who does. My suggestions account for this.

General design: open source, modable, upgradable.

Motion system: delta - bed doesn't move, or
core-xy - bed moves only in Z or not at all depending on design

Note a delta printer with a circular bed of X diameter will print smaller SQUARE parts than a cartesian printer of X length and width. Look up how big a square can you put into a circle.

Heated bed, up to 100 C.

Bed surface: 4mm glass substrate or equally thick aluminum. Magnetic surface with removable flexible textured PEI over spring steel. Can have textured PEI on the other side, or something else. Multiple different spring steel surfaces can be used.

Bed leveling: manual control to a reasonable level if bed moves, then AUTOMATIC bed leveling with preferably a permanently attached sensor or at least an attachable sensor.

Extruder hot end: all metal. Ruby or diamond or hardened steel nozzle optional if using abrasive filaments. Should be easily replaceable. Up to 260 C. Some hot ends have a PTFE (Teflon) core which emits toxic fumes at 250 C.

Extruder cooling fans: Quality units with ball bearings if possible. Hydrostatic fluid bearings (not sure of trade name) may be better. Sleeve bearings are not. Should be easily replaceable.

Part cooling duct: should blow air on part from as close to 360 degrees as possible. May be able to print your own upgrades.

Quality MOSFET's and heat sinks for controlling heaters. Can be added separately.

Stepper motor drivers (chips): newer style (don't remember the numbers) with quiet and smooth operation.

Controller: 32 bit with adequate I/O for all heaters, fans, sensors, servos, displays, etc. Sensors may include bed leveling sensors (which may require a servo port), filament run out sensors, temperature sensors, etc.

Firmware: Open source Marlin or Klipper (requires Raspberry Pi external computer). Three are other options as well.

Dry box or dehumidifier for filament.

Smooth running filament spool holder system.

Nice grippy feet under the printer.

Fire resistant printer enclosure with ventilation port.

Active variable speed ventilation system with hose and window vent. Look up grow tent ventilation for ideas.

Slicer: Super Slicer

Power supply: Safe and capable with shielded high voltage wires, switch, fuse, and active cooling.

That's all I can think of at the moment. Might think of more later. But, this should get you started. ;) ;)

Edit: PS in my opinion, avoid 3D resin printers like the plague. Resin is VERY toxic, requires special safety gear, is really hard to clean up properly, and can poison the local ecology if disposed of incorrectly.

Edit: PPS I knew I'd think of other things. If the printer has Z axis drive screws, they should be mechanically synchronized with gears or gear belts or chains so they all turn exactly in tandem. If not, the printer should have only ONE Z axis screw. Low backlash screw fittings are helpful. The couplers which couple the Z axis to the stepper motor(s) should NOT allow vertical flexing.

May your bits be stable and your interfaces be fast. :cool: Ron
 
Last edited:
@Ron, that covered a lot of good information. One of the things I liked about my Quidi was a quick easy setup. It does require manual level with a supplied plastic sheet for the purpose, and it came with some spare parts, screws, nozzle, and a couple wrenches. There are unquestionably better machines out there but I don't have too many complaints about it. Although I could, I didn't want to spend a lot of time playing with the printer itself, I bought it with the purpose of printing. For now, tinkering with all the settings is enough experimenting. I did buy a hardened nozzle for it.

I've read much about humidity and filaments. Some time back I bought a box of very thick metal film zip lock bags which were spec'ed for very low humidity leakage. I bought them for film negative boxes, but as it happens they fit filament spools as well. I label the bags with the color (you can't see thru the metal film) and keep a container of silica gel inside. I've printed a number of silica gel containers but found many a little too fragile, a couple I just couldn't get my printer to print well. I don't put the container inside the spool since the bags are flexible and may seal off drying only the middle, I drop them on the outside instead.

Another problem with many silica containers is the openings are a bit large so that broken gel pieces come out of the holes. I use bulk gel. If anyone wants to print gel containers one of the best I found is called a "dry sphere". It printed easy with PLA and PETG, has many small holes, and unscrews at 'the equator' so it can be filled and emptied. It may come as no surprise but ChatGPT has come up with some interesting info on settings for different filaments.

3D printers are complex with many available. After much reading I finally made what I thought was a good choice knowing the research would never end and there will constantly be new printers out there. That realization, and some impatience I bought mine.
 
  • Like
Reactions: rfrazier
that covered a lot of good information

You're sharing some cool info as well. I had a few other random thoughts I figured I'd share.

Here are a couple of humidity related products I've ordered that look promising. I haven't had much chance to experiment with them. The silica gel product is the "indicating" type which changes color when it's saturated with humidity. For some products, you can refresh the gel "pebbles" in a low temperature oven or food dehydrator. I read that the blue indicating desiccant products contain cobalt and should be avoided.

5 Gram [100 Packets] Premium Silica Gel Orange Indicating(Orange to Dark Green) Silica Gel Packets Desiccant

Dry & Dry Premium Humidity Indicator Cards 20 Pack(Reusable)

Here are the dehydrators I bought. Note that dehydrators with mechanical thermostats have about a +/- 25 deg F variance. Digital units are much better IF they have a good calibrated sensor.

Presto 06301 Dehydro Digital Electric Food Dehydrator

Sovol Filament Dryer, SH01 Filament Dehydrator 3D Printer Spool Holder

Here's another thought for those not familiar with 3D printers. Pay special attention if you have kids and pets. The hot parts (bed and extruder) of a 3D printer are, well ... *** HOT ***. Really hot. A printer bed at 100 C is 212 F or the boiling point of water. The extruder at up to 260 C is 500 F. This will burn you or your pet or your child INSTANTLY if you touch it. Self evident, you say. Maybe. It was self evident to me until I barely grazed the nozzle once and had a painful burn on my finger for days. Then, it was even MORE evident. Also, what may not be obvious is that you have to do some maintenance on the hot end extruder with it on. Maybe not full temperature, but still way up there. The reason is that 1) the metals contract when they cool, and you might not be able to disassemble and reassemble when cold. 2) The other reason is that when the extruder is cold, the filament solidifies within it, further hampering disassembly and reassembly. You don't necessarily have to have the bed hot to work on the extruder, but you do have to have everything up to at least low temperature for the best calibration (disregard if bed sensor is in contact with extruder). Also, if you're working on a hot extruder, you have to have somewhere to put the hot parts. Do NOT use paper or plastic or cardboard plates or bowls. 500 F is past the ignition point of paper and past the melting point of many plastics. Also, if you attach an adjustable wrench to a hot extruder nozzle, the wrench itself will quickly become too hot to hold. Don't ask me how I know.

EDIT: PS A multimeter with a K Type thermocouple can be handy, preferably one that takes any K Type probe and not only their proprietary one. A laser infrared thermometer can be handy as well to measure temperature. NOTE, the laser is only for aiming and they're usually way off. The laser has nothing to do with where the instrument is actually reading. (The laser and sensor are supposed to point at the same place.) You have to aim the body of the instrument directly at the spot you want to measure and account for distance. If the ad says something like 12:1 spot size or something, it will measure a 1" spot of area if it's 12" away from the target. Here are just a couple of options that came up on Amazon with high reviews. Dirt cheap instruments are rarely good, if even usable. You usually don't get what you don't pay for. I have not tested these specific products.

Klein Tools MM400 Multimeter, Digital Auto Ranging, AC/DC Voltage, Current, Capacitance, Frequency, Duty-Cycle, Diode, Continuity, Temp 600V, Orange

Klein Tools IR1 Infrared Thermometer, Digital Laser Gun is Non-Contact Thermometer with a Temperature Range -4 to 752-Degree Fahrenheit

Anyway, those were just some more thoughts that came to mind. Hope it helps.

May your bits be stable and your interfaces be fast. :cool: Ron
 
Last edited:
  • Like
Reactions: SeanBZA and Ralph
I have an IR thermometer but never thought to check my bed temp against it. I have just been going by what the printer is set to and displaying. Right about the blue indicating silica gel being toxic. I am fairly certain the orange/ green indicating gel is OK. Safest would be what I most recently bought, white gel. Since it has no way of letting you know if it is saturated about the easiest thing which I use are indicating cards. They come in various ranges of % relative humidity. I suppose digital gauges would work but they are more expensive and require batteries. I've been using blue indicator cards but they have the orange as well at a slightly higher price.

If buying gel in bulk you want 'type A'. There are different bead sizes given in millimeter ranges. If printing your own holders you may want to keep away from the smallest size beads so they don't slip through the container openings, or maybe worse yet so broken bead pieces don't fall out of the holder. I had a long chatgpt (of cause :) about silica gel to find out how much gel per cubic inch and other info. With a little care you can reactivate your gel in a microwave instead of hours in an oven. In a microwave you should take the beads out of PLA containers, they soften from the heat and will easily deform (don't ask how I know). You also don't want to overheat the beads. I give them 30 to 45 seconds then let them cool and give off moisture before heating again. PETG containers should hold up better in a microwave but I haven't tried that yet. The 30/ 40/ 50% RH indicating cards seem to work well, but as long as they indicate fairly low levels any range should work.

I've done a lot of reading on humidity and silica gel, mostly for storing film negatives and slides. Canning/ Mason jars are handy for storing loose gel. I keep an indicator in the jar. Canning jars have a good seal so activated gel will keep good in them too. Although I haven't, depending on your container you can put gel packages in them which would eliminate broken piece problems. The cheapest route is buying gel in bulk. The packs are on the expensive side for the amount of gel they contain, but packs are easier to handle and maintain.

BTW, plastics such as magnetic recording tape also absorb moisture over time. We used to have issues with computer tapes and humidity. Floating around somewhere I have a copy of a NASA publication about recording tape and humidity. If nothing else high humidity speeds up head wear quite a bit along with other problems like tape sticking to heads and oxide buildup on heads.
 
Last edited:
  • Like
Reactions: rfrazier
A good video! While I haven't looked at any of those printers specifically I can't find fault with what he says. As mentioned, before buying one I asked myself what would I do with it. After checking out a few 3d sites I changed my question to what can't I do with it. I liked a sign I recently saw, it said "Don't worry, I can print another one".

The one drawback for me of having all those models to download is I haven't put enough effort into learning how to make 3D models. Early on I started using FreeCad but never got much past using it's built in models to make simple objects. There are SO MANY models available, many free, some for literally under $1 from some very talented and creative people, and often just what I needed.

Rather than just printing a lot of practice things of no use other than to recycle, I started printing various toys and gadgets for a 5 year old relative. He enjoys playing with them and I get practice playing around with all the settings on the printer to see how they work and interact. I doubt I'll ever figure them all out, but my prints have gotten a lot better.
 
  • Like
Reactions: rfrazier
never thought to check my bed temp against it

storing film negatives and slides

recording tape also absorb moisture over time

Here are a few more factoids that might be useful. If using an IR thermometer to measure 3D printer heat bed temperature, you cannot point it at aluminum or glass or anything reflective. You need a matte dark finish. You can add electrical tape, dark painter's tape, or a dark surface sticker (Build Tak or clone), etc. I've found the adhesives on electrical tape and painter's tape to get gooey over time, especially if they're hot. So, you might not want to leave the tape on. It will be hard to use an IR thermometer to measure the extruder. Thermistors on 3D printers can often be off by several degrees. This can be important. But, check the tolerance on your IR thermometer too, those can also often have a wide variance. That's why I didn't quote an ad for the cheapest one on Amazon.

For a long and interesting rabbit hole about conserving old media, check out Association For Recorded Sound Collections. I'm sure there are similar organizations for video and film. I was on their mailing list at one time but just didn't have time for it. As I recall, it's a very busy list. You can also look up the work of archivists.



I've also studied humidity a good bit. Partly to keep it out of my house, since it's routinely 90 F and 90 % humidity here in GA. Partly related to 3D printers. I've discovered that, to get a good hygrometer (humidity meter), you really have to get up around $ 50. This product has a +/- 3 % tolerance I think. I've found that cheap meters, like the little digital ones for $ 3 each, are OK for temperature and pretty worthless for humidity. I've also found that cheap mechanical meters like the ones on wall weather instruments are pretty worthless.

EXTECH Instruments Digit Thermometer

Edit: PS Just thought of this. Some may know this. Some may not. An IR thermometer is NOT generally a long distance device. If it says 10:1 spot size, for example, that means it will measure a 1" circle if you're holding it 10" from the target. Again, the laser, even if it's aligned right, does NOT indicate that you're measuring just where the dot is. Also, if you're holding the IR thermometer 10 FEET from the target, in this example, it will measure a 1 FOOT circle, even though the laser is only illuminating a small point. The further away from the target you are, the more likelihood that the laser will point at a different place than the sensor. Something to keep in mind.

Hope that helps.

May your bits be stable and your interfaces be fast. :cool: Ron
 
Last edited: