We install an upgraded extruder drive and print surface on our new Creality 3D printer, and our experience should be similar to that for other brands of printer, too.
In reviewing the Creality CR-10S Pro V2 recently, which we purchased from Aurarum to replace our aging Lulzbot Taz 6 that was beyond economical repair, we acknowledged that it wasn’t perfect. We chose it because it had the best features and performance for the price, and was available while others were out of stock.
While we do like our new printer, there were several challenges that became apparent after a hundred or so hours of printing. Chief among these is a failure tendency in the push-fit connector that holds the Bowden feed tube onto the hot end. It has a habit of letting go while the extruder motor keeps feeding. As the primary operator of our 3D printer suite, this meant several mornings of me walking into the workshop to be greeted by a twenty-, thirty-, even forty-metre coil of filament on the ground and a nozzle moving around in mid-air. Of course, it was also my job to carefully hand-wind the filament back onto the spool, making sure I didn’t cross over or otherwise jam any turns.
This is partly because many of the push-fit connectors used on 3D printers, even good brands, are cheap Chinese-made generic items, with a thin sheet steel tooth system to grip the PTFE Bowden tube. My immediate solution was to buy SMC branded fittings from a local hydraulic and pneumatic supplier. These things are rated for very high pressures, in the order of tens of Bars (or hundreds of PSI because the imperial system still permeates retail pressurised air products) and have a much better release when pressed. They are made from well-engineered internal plastic mechanisms which grip differently to thin sheet steel teeth digging in. However, they are made for pneumatic lines, which are generally nylon or several other semi-rigid, high-strength plastics. Even though these plastics are, in the grand scheme of things, low friction, they are not nearly as low friction as the PTFE tubes on the Bowden extruders.
The result of this was less frequent but continued failures. That put us in mind to upgrade our printer to a direct drive extruder system. Genuine Creality upgrades, as well as several aftermarket brands, are available. Direct Drive Extruders (DDX) have the advantage of eliminating the feed tube between drive motor and hot-end: They mount directly over the hot-end and feed filament from the motor straight to the nozzle via a very short tube. This also means that extrusion is more controlled, because there is no slack or elasticity between the drive point and nozzle. The feed tube on a Bowden system allows enough ‘give’ that it is sometimes the origin of oozing or over-extrusions. The disadvantage is extra bulk and weight on the mobile print head, which can cause imprecise movement of the print head if belt tension is not maintained or the drive system not designed to cope.
Incidentally, my own personal Flashforge Guider II lives in the DIYODE workshop, and it is a DDX machine as-produced. It uses a different system for its print head, which is held securely on guide rails and the z-axis is actually a print bed on lead screws. This helps cope with the weight of the DDX print head and keeps it stable. However, Creality produces a DDX upgrade themselves, so it feels reasonable to assume the printer can cope with it.
The other challenge we discovered is the print surface. While great for the first few prints, it did not take long before removing the prints became a problem. Even when allowing the bed to fully cool, prints were difficult to remove without great force. The photos show several gouges and deep scratches where using tools to remove prints has damaged the soft surface. The first remedy was to adjust the z-axis clearance between nozzle and print bed. However, even when pushing the boundaries until filament almost didn’t stick to the bed at all on the first layer, prints were still anchored like super glue. Accordingly, with the team sharing the feeling that change was needed, I set about researching options.
However, before I got far, an email arrived from Aurimas at Aurarum. After reading our review, and not being aware of the office discussion around upgrades, he offered to send us an upgraded extruder assembly for the Bowden system, and a new print surface to try with our new printer. These were upgrades he felt we, and readers who read the first review, would benefit from. The extruder upgrade is a Bondtech branded unit, some of the best in the business. It is a replacement for the existing drive, utilising the same motor, but with a 3:1 reduction. This makes feeding three times as precise. It also has a different extruder gear design, for a more positive grip on the filament.
Further, it has a single path from the filament sensor, through the extruder, and into the Bowden tube. The stock system crosses two gaps at marginally different alignments, mandating that the end of the filament be withdrawn and slightly bent or straightened until an attempt at getting it all the way into the feed tube succeeds. The new system also has a filament tension lever that is secured by a thumb-screw, rather than the stock spring-loaded lever, so you can feed the filament then lock it down. This is especially important in unloading filament. Currently, one hand has to hole the spring-lever down so that the filament can be withdrawn with the other hand, leaving no way to carefully spool the withdrawn filament.
On many occasions, this has led to a situation where layers on the spool, with no tension left on them, spring out off the spool and have to be wound back on. Having a layer crossed over another, which then gets caught and locked down by the layer over it, causes the spool to stop feeding and the filament dive gear to gouge a dent in the filament instead of feeding it. Not only does this make a powdery mess to clean up, it means the print continues with no material extruded, as the filament run-out sensor still has filament in it.
I particularly, and anyone else in the office who uses the workshop, are looking forward to seeing the back of this problem. Having said that, the DIYODE-owned CR-10S Pro V2 has not done this to us too often. Some of the experience comes from the similar CR-X that I personally own, which is also here in the DIYODE workshop. While we are still keen to try DDX, this extruder seems worth a go.
The print bed Aurarum sent is a visually impressive item as well as giving great hope of being practical. It is a thin sheet steel flexible bed with powder-coated Polyetherimide (PEI) on both sides. One side has a slightly finer texture, but whether by design or accident, I don’t know. This sheet sticks to a magnetic base that is supplied with it, to completely replace the stock bed. PEI is supposed to have great adhesion when warm and much less when cool. However, the surface is designed to be printed with no bed heating for suitable filaments, and it is said to be adhesive enough for this but not so much that prints are hard to remove. The flexible surface helps with this.
INSTALLING THE EXTRUDER
Installing the extruder is relatively straightforward. The kit comes with QR codes, or directions to Bondtech’s website, for set-by-step instructions and supporting photographs. The only tools you’ll need are three hex keys, and the ones that came with the printer should be fine.
After examining the step-by-step website instructions for hardware installation, I discovered that the steps are very clear, with lots of colour-coding and also multiple photos showing the progression of a step where relevant. You hover the mouse over the thumbnail and the larger shot appears as the main step photo. This was particularly helpful.
The process went smoothly and before long, the extruder drive was installed. The entire process took around ten minutes, including double-checking the instructions. The hardest part was removing the Bowden tube from the old push-fit connector on the stock extruder - pliers were needed to push the connector hard, and a firm pull needed to get the tube out. The damage to the tube from the aftermarket stronger connector we fitted indicates why. Whoops. The only other minor challenge was getting the stepper motor drive gear into the extruder - the gear has a ring around the top which takes a bit of, as the instructions put it, ‘wiggling and a little bit of force’.
After installation, there are firmware changes to be made. For CR-10S Pro machines, firmware is provided. For Pro V2 machines with BL Touch, do NOT use this firware. Stick with the stock firmware and alter the settings from within Creality slicer to change the e-step to 415 and the upper limit to 385mm. If you get stuck, Bondtech's customer service is pretty good!
Lastly, there is a third set of instructions to allow the current settings for the stepper motor to be changed. The instructions are very clear but you will need fine probe tips on a multimeter and a plastic adjustment tool.
INSTALLING THE PRINT BED
Installing the print bed was even easier than the extruder. The bed has no instructions, physically or digitally, so we winged it. The first step was to power up the unit and move the print head to the top of the gantry by using the ‘move axis’ settings. With the workspace clear, we unclipped the tabs holding on the stock print surface.
It was tempting to remove the existing build plate tape from the aluminium bed and stick the magnetic base to it. This would preserve the heater surface underneath for any future changes. However, the clips used to secure the bed looked to be too tall. A careful measurement revealed that they would protrude above the magnet surface by 0.2mm. Combined with the BL Touch levelling system and their position right at the edge of the print area, we felt that even if they bend the PEI plate slightly, it won’t be an issue.
Accordingly, we heated up the print bed to 110°C to help the build plate tape soften and the adhesive become removable, then put on gloves to help stop burns. With the bed hot, the front clips were swung open while the rear clips were used to help hold the plate while the tape was removed from the front. It was then flipped around for the process to continue. It proved to be a painless process.
That done, the bed was allowed to cool and then cleaned with isopropyl alcohol to remove adhesive residue. Then, the magnetic plate was centred and small cuts made to accommodate the bed clips. The 3M-brand backing tape was peeled, and the magnetic tape placed. Extreme precision is required here: The stock build plate is 310 x 320mm, while the new one is 320 x 320mm. It will slightly touch the gantry sides, so take care that there is still free movement. That’s the only catch to the whole process.
Sadly, this installation arrived too close to print time to give the system a real test. However, the whole team was too keen to wait. Most of these things work at first - so did the stock system. However, on the basis of the initial prints that I did have time to produce, I can say this: The new extruder has made filament loading and unloading much, much easier. Inserting new filament is smooth and without obstacles. Unloading filament is much, much safer and now one hand is free to spool the filament back on properly and control the free end. The system felt more positive and the difference made by the 3:1 gears was visible while watching the print run its course. This is especially true after fiddling with the retraction settings. The issue of the hot-end push-fit connector releasing is nothing to do with this upgrade but it only happens sometimes and didn’t during this test. We tried a different brand of fitting and it seems to have stronger teeth anyway. It just doesn’t come back out when I ask it to!
The print bed is also impressive. While acknowledging that the stock one went well at first too, signs are good. The first print was left to run overnight, and while the overnight low of 7°C may have helped the contraction, the print popped straight off with only finger pressure. Adhesion was also trouble-free once the appropriate clearance had been worked out. There isn’t enough left to say to justify a follow-up review, so keep an eye on socials for updates. We will continue to put the extruder and print bed through their paces, but I suspect the days of hammering prints off beds or arriving to find a print released while still printing are behind me!
The extruder drive and print surface are available from Aurarum: