Dimensional Print Studio

I have my newest Tiertime Cetus, I call Big MamaCatus, doing some prints I never thought I would do on a Cetus FDM printer.*

The Cetus printers do not have any mechanical leveling of the build plate. It is bolted directly to the linear bearing with three small screws with no method of adjustment. What you have for level is fixed.

The leveling is done by using a four-layer raft and a four-layer base support on top of the raft. The first layer of the raft is 300% over-extruded and squishes out broadly. This heavy first layer and the buildup of the raft and support eventually results in a build surface that is parallel to the X and Y axis. Then the print is started on top of this level surface.

The result is the use of a lot of filament material to build a flat working surface. With a Cetus printer, one throws away a lot of raft leveling material at the end of the print.

The raft and support do not provide a nice polished build surface for the base of the print. The print bottom is always ruff like about #80 grit sandpaper. I usually “flame polish” the bottom to remove the little sharp points, but the surface is still quite a bit grainy.

I have installed a 3mm thick sheet of borate glass 200mm x 200mm using binder clips on the Cetus build plate. I simply tolerate the bit of non-level of the build surface. It is a bit larger than the 190mm x 200mm Cetus bed. I can live with a bit of overhang as well as the level issue.

I have to remove the ~5mm excess nozzle calibration height to get the nozzle low enough to print without the raft and support layers. 

What I get is perfectly smooth bottom prints from Big MamaCetus! (*Read the first line above again.) I can stick some thin Build-Tac on the glass for TPU and PETG.

I am exceedingly pleased to be able to print without the raft. Some prints may still need the raft if I run into serious leveling issues on a big print. I have had no serious issues with prints up to 100mm diameter so far. First layers may be a bit thin on the high side but as long as the low side will stay attached to the build surface, the second layer evens out the height. I can not see this slight deviation in any of my finished prints.

Big MamaCetus is a MK3 with a heated build surface and the auto level probe. Early electrical problems have been resolved. (See previous posts.) I still consider the flexible power ribbon connected to the heated bed a weakness in design of the MK3. Careful protection of the cable must be maintained. I know to be careful.

The picture shows BMC printing a PETG cap and the glass build-plate with build-tac surface. Nozzle temp is 240C and the bed is 85C.  55mm/s speed. The print is excellent.

Working with a new filament type for FDM (Fused Deposition Modeling). Called TPU (Thermoplastic Polyurethane) It produces rubber-like flexible prints. Many producers and brands. I have no way to evaluate, so I picked a brand “Overture”.

I read a lot of prose on what brands are best. Most of what is printed is pure BS. It is like picking which tree in the forest has the best wood for your current woodworking project. Real craft people can adjust for slight variation in materials and produce excellent products.

It’s also like baking cookies. There are always slight variations in flour brands and also various “grades” of flour.  Bread and cake flour are both still flour.  OK - rant over…

I am learning how to work with my new TPU. 

The TPU filament is like boiled spaghetti, a bit past “al dente”. It is SOFT! Very flexible. For that reason, the suggested print speed range is between 20 to 40 mm/s with 40 really pushing it. It seems 10 to 20 mm/s is a great speed for printing. No so good if you think FDM goodness is judged better by how fast you can go…

I also noticed material is extremely under fed and I have pushed extrusion multiplier to 1.5 (150%). Most PLA and other hard filaments I run between. 0.9 and 1.0 for example.

I am also playing with UPStudio3 (BETA) using my CETUS Mk3 printer with heated bed. CETUS has a very closed coupled direct drive filament feeder. I cannot see TPU working well with ANY Bowden type printer. I have not tried, but with all the filament flex, a Bowden feed will be total frustration controlling the print.

Suffice, the Cetus drive is working very well.  UPStudio3(beta) is not quite ready for “prime time” for use with Cetus. It works, but there are limitations that must be removed before getting my stamp or approval as an everyone’s slicer/ printer.

The next step with my new TPU material is discovering what it can print. Things that must be flexible. How do printed supports work with TPU? I will be “playing” with TPU and looking for the “killer application” that needs to be made with TPU.

My soda can cap in the picture is a good start. The very first print was air permeable (not airtight) so will experiment with line widths and flow rates. A rubber cap should seal…  all part of mastering the process.

My Big Mama CetusBMC, Big MamaCetus now lives up to her promise and expectations.

After being abandoned by Tiertime (Cetus) support, I have been on my own to trouble shoot and fix the problems with the Cetus MK III printer.

What I think led to the issues was my lack of knowledge of how the multiconductor ribbon cable termination sockets mechanically function. Absolutely no instruction was provided by Tiertime on the process to open/close or unlock/lock the connectors.

Looking at these very small connectors, I assumed (incorrectly) they were simply friction fit terminations. This was false. There exists a very tiny lock/unlock bar to clamp and unclamp the termination to properly insert and remove the cable from the connection.

I was able to force fit (with rather moderate effort) the ribbon cable into these sockets without releasing the clamp bar. But something went astray from the high current 20 conductor ribbon cable to the heated build surface. One conductor in the center of the cable vaporized when I first enabled the power. The trace is supposed to be non-connected as an empty buffer between the plus and minus high current leads on both sides of this unused trace.

Somehow it conducted a high amount of current, which made it glowing hot.  This short circuit COULD and likely DID lead to all the other failures.

The issue was that the printer could still print but had no temperature control over the build surface. The build plate would power full on and become extremely HOT. Even melting PLA rafts to the build plate.  The CPU could not read the temperature sensor attached on-to the build plate.

Having no schematic or description of operation, I had to use my experience of how I thought it SHOULD work. Again, NO HELP was available form Tiertime after the very first contact. That’s another story.

I discovered the micro SD memory card failed on the main board, and the CPU board never, ever produced a WiFi signal. The Build Plate cable was the only visible damage and was obviously bad. The cable is not available as a repair part. Tiertime did send me a new build plate with a new cable. I also bought a second replacement just to have another good spare cable on hand. It is an obvious weak point in the bed heating system.

The new build plate cable didn’t fix the issue of not reading the build plate temperature. There is a signal problem between the build plate and the CPU.

At this point Tiertime stopped responding to my subsequent attempts to communicate.  At least six more attempts through website and Facebook.

I bought (paid for) a new intermediate control board and a new CPU unit. Both came with necessary cabling, so all in the signal path was changed. The order department in China is very responsive to paid orders. I received the new parts 3 full days ahead of promised delivery.

After installing all the new parts, Big Mama Cetus was powered up again. Glory Hallelujah! Everything is working as it should. She is in perfect health.

I have now made a half dozen parts and all are perfect, top notch quality and all function of the printer are correct. Cetus MK III is a great tool when wired correctly and all components are in working condition.

I have been constructing electronic components since I was 10 years old. I am presently 73. Sixty three years of experience and a ham radio builder and licensed for over fifty years. I know my way around electronics. I am a career expert in electronic and all other types of environmental and machine control systems. The average Joe is going to have no idea how to solve these types of issues.

Can I recommend Tiertime and Cetus?  I think the product is not perfect, but the two I own demonstrate I do like how they work.  Currently, I think the support group is in a mess and un-supportive. Published support information is disjointed and randomly arranged. Scattered.  Look long and hard, there is good information. But a vast amount of conjecture and guessing from “user forum” type comments.

In my honest opinion, User Forums is NOT a good way to provide customer support. Too much “chaff” for the few grains of valid information.

Failed 20 conductor ribbon cable.The new Tiertime Cetus Mk3 3D printer has been a real test of my trouble solving skills and patience with a non-communitive Cetus support team.

The basic printer is as good as my original Cetus. The problem is the addition of a heated build plate. That requires a secondary control board mounted on the Z axis column. It’s fed with a 24-volt power system. The bed is 160 watts.

A very thin, flexible 20 conductor ribbon cable is the connection between the 160-watt heated build plate and the secondary control board.  The 24-volt power brick feeds into the Auxiliary board first before feeding the main system board through another power cable.

Two parallel 8 conductor (trace) groups in the very thin ribbon cable carry the 6.7 AMPS of current to and from the heated build plate. Two more conductors (traces) together on one side carry the signal voltage for the temperature sensor on the heated build plate.

No instructions other than to “connect the ribbon cable” face up or face down are provided. There exists a microscopically small clamp-bar that needs to be open/closed to install and remove the ribbon cable from the termination block. It’s a secret I had to learn the hard way.

I fried the first cable when the unused “safety” conductor trace between the 24V, 6.7A  plus and minus groups MELTED as it shorted between them. Not sure of the exact cause mechanics. But that single trace had to be carrying a very high current.

I re-fit the cable after discovering the clamp/unclamp feature. The printer seemed undamaged. The melted cable still operated! I did some PLA prints and some new wax filament prints. But I noticed the bed temperature was very erratic and out of control. The build surface was getting far too hot.

The fact is there is NO temperature control of the heated build surface.  It simply runs full-bore.

First contact with Cetus/Tiertime support got me a replacement build plate. I also bought (paid) for a second replacement build plate. Apparently the 20-conductor ribbon cable is not available separately. (That’s extremely ignorant!)

The build plate is not the problem, the melted cable is. That’s why I wanted a spare AT ANY COST.

The new bed/cable did not solve the problem. Temperature reading were very unstable and jumping back and forth.  I discovered a tiny slice in the edge of the new cable that partially cut the trace carrying the temperature sensor. The flexing of the cable with the print surface movement was like bending a paperclip until it breaks. An ohm/continuity test of that trace shows it finally failed full open. 

The third cable was tested, and all 20 leads are fine. However, there is still no reading of the print surface temperature. 

At this point Cetus/Tiertime is totally ignoring my in-depth investigation and reporting and my many requests for further assistance. Total lack of customer respect and communication.

I have ordered a replacement intermediate controller board as the signal for the temperature reading seems to be processed on this board. It’s a multi-layer PC board so circuit tracing is mostly a guess. 

There are no circuit schematics available of which I am aware.

Two other problems also manifested on the control system. The 8GB micro SD card became unreadable. I replaced it with one I had. This “fixed” the 50C degree low (but tracking) temp readings. Now I only see a fixed 19+C read. Also, the Wi-Fi has never operated from day one. Both of those involve the main processor, so I have ordered (at my own expense) a new CPU board.

I now have an additional $200 invested into the Cetus Mk3.  Not acceptable by anyone’s standards. I just want an operational Cetus Mk3 so I can run wax printing. Some (low) controlled heating of the build surface is a requirement.

In my experience, all forms of 3D printing hardware require extreme user trouble shooting fix and repair abilities. Properly operating hardware still requires extreme effect/cause diagnostic skills because of the very high number of inter-reactive variables of hardware and software and also printable design requirements. 

There are a great number of fails before success and a huge supply of bogus internet advice.  The internet never deletes outdated or erroneous information. Dealing with difference in language and non-standard terms just adds to the confusion.

However, that is no excuse for Tiertime/Cetus  ignoring a paid-in-full customer in need.