The Printer I Hate to Love
The printer I hate to love. That's how I have to describe my affair with the Tiertime Cetus 3D printer. It's a wonderful minimalist 3D printer with more than its share of problems. When it is working and printing, it can produce excellent prints. Tiertime is always changing (evolving) both the design and the software.
The big issue for me is solid temperature control for both bed and nozzle on version MK3 Cetus. I have experienced random temp extremes in both heated areas.
MK3 CPU operation will occasionally software-seize after loading a run file from the new Beta UPStudio3. It involves the heated bed temperature control. The only way to clear the block is to run UPStudio2, then manually command the heated bed to preheat for about 10 seconds. This action resets something in the Cetus firmware. The occurrence is rare but definitely repeatable.
The new V2 hot end extruder has issues. It contains a PTF tube in the nozzle feed cold end. It is NOT all-metal. Twice during a retract (change filament) operation I have had the temp control fail and the nozzle temp rise to 300 degrees Celsius. This deforms the PTF tube requiring full length nozzle replacement.
The ensuing issue is the nozzle tube is a long-threaded brass tube and the heat block is a long-threaded aluminum hole. Experienced mechanics know brass to aluminum high heat environment the threads are subject to galling and seizing. Especially the fine pitched threads used by Tiertime on the nozzle. There appears there could be some sort of anti-galling material in thie original assembly but in my case it didn't work. Trying to extract the nozzle assembly from the aluminum heat block, stripped out the fine pitch aluminum threads.
I fitted a replacement nozzle, but with 90% of the aluminum threads stripped out. The heat transfer to the nozzle was extremely poor. Although the block would reach desired temperature, the nozzle itself was running far too cold for proper flow. I removed a small nozzle position locking brass bracket (held by the screw in picture) and tightened the nozzle shoulder assembly up flush to the heat block. This was a temporary heat transfer fix until the stripped-out heat block could be replaced. A new assembly is $58.00 with shipping.
I accidently tore the red silicon insulating rubber removing/replacing it on the aluminum block. I had to remove it to clamp the block in a vise to rip out the original nozzle. Shown in front is the replacement nozzle (good threads) that has also been overheated. This 2nd nozzle failure encouraged me to abandon this original heat block and order the replacement. The temporary repair did last for a few dozen prints.
The shipping was ~$17 UPS from California to Texas (maybe 6-9 oz with packing) and it will take a week. But that is a different issue. USPS would take 2 days.