This document is written for the new owner of a QIDI X-Plus3 filament printer. There will be some information useful for new owners of other printers and perhaps some information useful for more experienced owners.
I’m assuming you know little to nothing about 3d printers so I’ll take you through the basics.
After unpacking and removal of protective materials, you’ll need to check the power supplies for the correct settings. There are stickers on the bottom of the printer telling you how the power settings have been set. You do not need to take off the bottom panels to check the power supplies directly.
There are many types of 3d printers. We’ll be discussing filament printers, which use a spool of plastic filament. The spools generally come in 1 kg spools, 1.75mm diameter filament. There are many types of filaments. Your printer came with “rapid PLA”, a 500g spool.
PLA is an excellent general purpose filament. The “rapid” refers to the melt characteristics and the suitability for fast printers.
The “hot end” consists of a heater, a temperature sensor, and a nozzle. The nozzle is 0.4 mm which is a common standard. You also got a hardened nozzle spare hot end used for abrasive filaments. The installed one is copper. If you use an abrasive filament in a copper or brass nozzle, the abrasive filament will rapidly wear the 0.4mm opening. You must be aware of the filament you are using and you should know that certain colors or additives can make a filament abrasive.
The rate limiting factor for fast filament printers is the ability to melt large amounts of cold filament and bring it up to the extrusion temperature. Different metals transfer heat more or less efficiently. Copper is excellent. Steel less so. For slow printing it makes little difference but rapid printers put a lot of filament through the hot end rapidly so the efficiency of heat transfer becomes important to ensure the extrusion can keep up with the rapid print head movements. The characteristics of the filament make a big difference. If the filament goes through the hot end and isn’t sufficiently melted, it’ll clog the nozzle and likely ruin the print. You can print with a non-rapid filament but you won’t be able to print as fast. Since 3d prints generally take a lot of time to print, it is nice to be able to print rapidly.
Water absorption is something about which you should know. In general PLA filaments absorb some water but not enough to be troublesome so can be used in open air without much attention to water content. Other filaments will be more aggressive at absorbing water. The problem with water is that it is turned to steam in the hot end and bubbles of steam will interrupt the flow of molten filament from the nozzle. We usually measure humidity as “relative humidity”. This is a percentage of the maximum water the air can carry at a certain temperature, so at room temperature a relative humidity of 40% means the air has 40% of the total water it could hold at that temperature. The amount of water the air can carry goes way up as the air temperature increases. There’s another way to measure the water content of air, and that is absolute measurement of grams of water per volume of air. There are charts that will make the conversions if you are interested. But know that PLA is generally OK at normal room humidity but other filaments aren’t. There are a couple of ways to reduce the water in filament. Most often it’s done with heat, heating the filament and driving off water. You must be careful not to overheat the filament, too hot and your filament melts and that spool of filament is ruined. Kitchen ovens are notoriously inaccurate. You can use heat, just be careful about it. Another way to dry filament is to put the filament into a dry environment and the moisture will diffuse out of the filament into the drier air. Dry filament can be placed in a dry box to prevent absorbing moisture.
Drying the air. People often use small balls of silica gel. Silica gel has an enormous surface area, a teaspoon has roughly the surface area of a basketball court. The silica gel is porous and that inner surface area will adsorb water. It takes outside air a while to equilibrate with the surface inside the silica gel particles. Also, silica gel doesn’t actively remove moisture, the surface area adsorbs water to maintain an equilibrium with surrounding air, so if the silica gel is dry, it’ll dry the air. Silica gel can be thought of as a sponge, it can also be used to increase humidity. Libraries use silica gel to maintain humidity levels at certain levels in their sealed exhibits. One can use silica gel to maintain any humidity one likes. Generally, we dry the gel then the gel dries the air as the moisture equilibrates with that huge inner surface. It takes time for the moist air to equilibrate, it can take days to weeks. Some silica gels have indicator granules. Generally, they’ll turn color at a fairly low water content, 13% for the blue ones, so there’s still some absorption capacity after color change. Some indicator granules are toxic, the blue ones contain cobalt chloride for example. The orange/green ones are nontoxic. If silica gel is aggressively dried in an oven, the water inside the gel particle turns to steam and that steam can fracture the granule.
One other way to dry the air is to use something that actively traps moisture. Canisters of calcium chloride are used to dry larger enclosed spaces (rooms, etc.). This salt takes up the moisture which liquifies the calcium chloride and traps the water as a salt solution. These canisters are inexpensive so can be discarded when exhausted. They’ll bring the relative humidity down to round about 20% at room temperatures and work until the dry calcium chloride becomes liquid.
There are other ways to dry air, such as air compression but those methods aren’t usually practical for us.
3d printing. Basically a computer design, or CAD program produces an “.STL” file. That contains the exact measurements of the item one wants to make. Next the file needs to be “sliced”. The slicer takes the STL file and converts it to mostly movement commands but other commands as well, such as temperatures, fan speeds, speeds of axis movements, all the commands the printer needs to make your print. This is called the “gcode” file. Gcode tells the printer precisely each movement and each setting. Gcode will be optimized for the printer, the filament, and any other options you select. In order to ideally tailor the gcode, the slicer must have detailed information about the printer and the intended filament. The slicer must also provide supports where necessary. Once the file is properly sliced it can be sent to the printer.
Supports: The print is constructed in layers. If there’s an overhang, or inadequately supported part, you’ll need supports. You cannot print in midair so the slicer must provide a framework to support that area of the print. There are two types of supports, there’s the regular framework of traditional supports, and there’s an “organic” option. Once one has enabled supports, one can elect the organic setting which is much easier to remove later.
The printer will take the gcode file and start the print process.
The printer: The printer extrudes a line of molten filament. It must control the amount extruded, the timing of the extrusion, the temperature, and pressure in the melt chamber, and it must stop the extrusion precisely when necessary. It does this with the drive mechanism that pushes the filament into the hot end. It’s an exacting process, and that’s why filament manufacturers will generally tell you the precision of the diameter of the filament, “Tolerance 0.2mm” for example. This is important because the drive wheels in the print head calculate the movements based on the volume of plastic that needs to be extruded. Suppose the filament varied in diameter, then the drive wheels would move precisely but the variation in filament diameter would provide more or less plastic than necessary. We would see that as errors in the print, gobs, gaps, and uneven ridges in the final print. The more precise the filament, the better job the printer will do with the print.
Extrusion temperature: The filament isn’t like water which is either solid or liquid, filaments are plastic so increasing the temperature will generally make the semi-molten plastic runnier. As the filament is extruded it needs to melt and fuse to the previous layer. Next the extruded plastic needs to be rapidly cooled so it becomes solid to provide a good base for the next layer. This is done with fans. When everything is perfect, you get a strong and great looking print. If the extrusion temperature is too hot and/or cooling inadequate you get “stringing” which refers to small cobweb like strands of plastic going across parts of your print where there shouldn’t be plastic strands. If the extrusion temperature is too cold, the plastic is less liquid so may not be extruded fast enough to properly print. You may see gaps in the print. You can see poor adhesion between layers so the print can be weak and can break between these weakly fused layers. There’s a fairly narrow range of temperatures that work ideally.
Bed adhesion: To properly print, a layer of plastic must stick to the print bed. This forms the basis for the print. If the print doesn’t stick to the bed, the next layer extruded plastic has nothing to stick to. The printer continues to print faithfully executing the commands, precisely extruding plastic but the plastic makes a mess. It can be a glob of molten plastic stuck to the extruder nozzle or if the filament is extruded out into open space, it forms a big mass of “spaghetti”. In any case the print is ruined, time, and filament is wasted. So, adhesion of the filament to the plate is crucial. Plates are designed to provide a good anchor for the first layer. Still, sometimes extra is needed. Suppose you want to print something with a small base but is tall. There’s a certain amount of friction or “pull” as the nozzle deposits plastic on the previous layer. As the height of the print goes higher, the torque on the area of the print stuck to the base plate increases. If there’s poor adhesion, the print breaks loose. You can increase adhesion by properly heating the base plate. Sometimes a few degrees warmer will really aid adhesion. Another thing one can do is artificially widen the area of adhesion to the base plate by printing a “brim”.
It is important that the base plate provide ideal adhesion for that first layer. I wipe the base plate with a paper towel moistened with 70% rubbing alcohol before every print. This removes any oils and mechanically removes any loose small plastic particles that might remain from the previous print. After the print is complete one must remove the print from the base plate. Now that previous “ideal adhesion” can challenge print removal from the plate. If the plate cools, there’s a difference in the amount of cooling induced shrinkage of the base plate versus the plastic, so the print loosens. The base plate on the X-Plus3 is magnetically held to the support plate so can be quickly removed. The plate can be flexed so one can break contact between the base plate and the print if the baseplate is flexed. If I don’t want to wait for the base plate to cool, I’ll put it in the refrigerator for a minute or so and the prints loosen. A chisel is provided with the printer but I’d rather avoid using it. If the print is solidly stuck to the base plate material is then chiseled loose, there may be a possibility with some printers of the base plate surface coating sticking to the print and separating from the build plate. While that may not be a problem, I’ll avoid the whole issue by allowing cooling to loosen my prints.
There’s a filament runout sensor on the X-Plus3. It may not be enabled as shipped. There’s a setting in the printer’s setup to enable it. Use the setup icon, select the “load” menu and you’ll see the icon on the right side, second icon down. When enabled the printer will sense the end of the strand of filament and pause the print.
Changing filament: There’s a manual extrusion setup on the printer display. You can move filament up and down. So, if you move it up you back up the filament out of the print head, if you move it down, you advance filament into the print head. With the hot end hot you can advance the new filament into the hot end. Make sure you advance enough filament to get an unbroken strand of extruded filament prior to resuming your print.
I think this should get you started.