3D printers have come a long way over the past several years, but the process of bed leveling remains a pain point. Let’s take a look at the different ways the problem has been tackled, and whether recent developments have succeeded in automating away the hassle.
Bed leveling and first layer calibration tends to trip up novices because getting it right requires experience and judgment calls, and getting it wrong means failed prints. These are things 3D printer operators learn to handle with time and experience, but they are still largely manual processes that are often discussed in ways that sound more like an art than anything else. Little wonder that there have been plenty of attempts to simplify the whole process.
Some consumer 3D printers are taking a new approach to bed leveling and first layer calibration, and one of those printers is the Anycubic Vyper, which offers a one-touch solution for novices and experienced users alike. We accepted Anycubic’s offer of a sample printer specifically to examine this new leveling approach, so let’s take a look at the latest in trying to automate away the sometimes stubborn task of 3D printer bed leveling.
If you’ve ever had the good fortune — or, after a shop mishap, the misfortune — to see the insides of a dial indicator, you’ll know the workings of these shop essentials resemble nothing so much as those of a fine Swiss watch. The pinions, gears, and springs within transmit the slightest movement of the instrument’s plunger to a series of dials, making even the tiniest of differences easy to spot.
Not every useful dial indicator needs to have those mechanical guts, nor even a dial for that matter. This compliant mechanism 3D-printed dial-free indicator is perfect for a lot of simple tasks, including the bed leveling chores that [SunShine] designed it for. Rather than print a bunch of gears and assemble them, [SunShine] chose to print the plunger, a fine set of flexible linkage arms, and a long lever arm to act as a needle. The needle is attached to a flexible fulcrum, which is part of the barrel that houses the plunger. Slight movements of the plunger within the barrel push or pull on the needle, amplifying them into an easily read deflection. When attached to the head of a 3D-printer and scanned over the bed, it’s easy to see even the slightest variation in height and make the corresponding adjustments. Check it out in the video below.
We’re big fans of compliant mechanisms, seeing them in everything from robot arms and legs to thrust vectoring for an RC plane. This might look like something from a cereal box, and it certainly doesn’t have the lasting power of a Starrett or Mitutoyo, but then again it costs essentially nothing, and we like that too.
How do you know if your 3D printer bed is levelled? Oh, don’t worry – you’ll know. Without a level bed, filament won’t stick properly to the build surface and you’ll run into all sorts of other problems. Knowing how tricky it can be to get the bed just right, [Antzy] built a tool to help.
The device, which he calls the FS-Touch, is based around an Arduino Pro Micro fitted with a force sensitive resistor. This allows the distance between the bed and nozzle to be measured based on the force read by the resistor when placed in between the two.
Using the tool is simple. First, the bed is brought roughly into alignment using the typical paper method. Then, a reading is taken from one corner of the bed, and the measurement saved for reference. The other corners can then be set to the same level, with the aid of LEDs to guide the user in which direction to turn the adjustment knobs.
Measuring force in this way has the potential of being more repeatable than the somewhat difficult paper method. It promises to ease the task for users that may be struggling to get their bed in proper shape. Of course, automated bed levelling makes things even easier again. Video after the break.
Conventional load cells, at least the ones you can pick up cheaply from the usual sources or harvest from old kitchen or bathroom scales, are usually way too big to be used on the extruder of a 3D-printer. [IvDm] wanted to build a touch sensor for his Hybercube printer, so he built his own load cell to do it. It consists of four 1000 ohm SMD resistors in the big 2512 device size. He mounted them to an X-shaped PCB and wired them in the classic Wheatstone bridge configuration, with two resistors on one side of the board and two on the other.
The extruder mounts into a hole in the center of the board and floats on it. Through an HX711 load cell driver chip, the bridge senses the slight flex of the board when the extruder bottoms out on the bed, and an ATtiny85 pulls a limit switch input to ground. [IvDm] even did some repeatability testing with this sensor and it turned out to be surprisingly consistent. The first minute or so of the video below shows it in action on the Hypercube.
Laser engraving and cutting has something in common with focusing the sun’s rays with a magnifying glass: good focus is critical to results. If materials of varying thicknesses are used, focus needs to be re-set every time the material changes, and manual focusing quickly becomes a chore. [Scorch Works] has a clever solution to avoid constant re-focusing that doesn’t involve sensors or motors of any sort. The result is a self-adjusting bed that compensates for material height changes, ensuring that the top surface of the material is always a fixed distance from the laser’s head.
The way [Scorch Works] has done this is to make two spring-loaded clamps from angle aluminum and a few pieces of hardware. When a sheet of material is placed into the machine, the edges get tucked underneath the aluminum “lips” while being pushed upward from beneath. By fixing the height of the top layer of angle aluminum, any sheet stock always ends up the same distance from the laser head regardless of the material’s thickness.
[Scorch Works] shows the assembly in action in the video embedded below, along with a few different ways to accommodate different materials and special cases, so be sure to check it out.
3D Printering: the final frontier. These are the voyages of another 3D printer hack. Its mission: to explore strange new ways of leveling a print bed.
So far, we’ve had servo probes, Allen key probes, Z-sled probes, inductive and capacitive contactless switches, just to name a few. All of them allow a 3D printer to probe its print bed, calculate a correction plane or mesh, and compensate for its own inherent, time variant, inaccuracies.
[Jeremie Francois] has been thinking about ways to improve tool height adjustment and bed leveling in his 3D printer for a long time. His dream was to never ever think about Z height again. A dream that’s shared by many. These days, a lot of 3D printers have a mechanism for auto leveling in the software of the 3D printer. This works pretty well, but for various mechanical reasons, it’s better to have the bed itself be level.
[Jeremie]’s approach is pretty clever. Since you can define any plane mathematically with three points, he has three Z-axis lead screws. This lets him tilt the bed at any angle he likes. Once he had the mechanics in place, he added some force sensitive resistors, an Arduino, and wrote an extension for the popular Marlin firmware. That’s when the problems started.
It turns out that solidly mounting the bed to the resistors transmitted way too many vibrations. The solution was a layer of neoprene rubber. The neoprene also acts as a cushion, so the nozzle won’t break the glass bed during the leveling procedure.
The video after the break is a bit wavy, due to YouTube’s terrible auto-stabilizing software, but if you watch closely, you can see the system at work.