Dimensional Print Studio

Original designI was kicking back wondering what kind of Three-Dimensional Print project I could design before Christmas 2020. Time is getting short. Whoa! Did I just think about time?

Some folks design and print the operating parts of a CLOCK. But usually, the 3D hobby printing process is a bit crude for fine gear work. I wasn’t thinking of the operational parts inside the clock. I am thinking about the case that contains the clock and the face where the time is displayed. 

The display could be old fashioned round analog dial or digital. I can and probably will design cases for both systems. Analog has a traditional appeal for me.

I figured there were probably dozens of makers of the actual clock mechanisms. A look on Amazon.com proved that was an accurate assumption.

I wanted something for a small case that would be easy to print on one of my smaller 3D printers. I found a series of 70mm analog clocks that simply press fit into a 61mm round opening. Woodworkers use these clock “works” in their wooden-made cases. Certainly, a perfect choice for a 3D Printed case.

I made a few pencil sketches then I fired up my favorite 3D CAD, Autodesk Fusion 360. In short order, I had my design drawn in CAD and out-put to an STL file. The STL file is fed to another computer program, Simplify3D. There it is sliced into hundreds of layers for 3D printing. A new file called G-Code is created by Simplify3D, which is sent to yet another computer in the 3D printer. It’s the G-Code that instructs all the actions the printer performs to make a 3D print.

I have printed five of my original design and purchased clock “works” for all of them. The actual clock (from Amazon.com) is in the $10-$15 range. They are gifts for friends and family. 

I then got really ambitious about clock cases and designed a larger clock for myself. It uses the same “works” as the other clocks. My inspiration was the Texas “Lone Star” logo. This clock maxed out the build surface on my two-color printer. 

All but one of my new small clocks were printed blending two colors of plastic in a two-color single nozzle printer. The Lone Star clock is also two-color print using a 50/50 mix of beige and brown. It required 17 hour 15 minutes to print. I almost ran out of brown filament.

I love the design stage and the 3D CAD as much, probably more than the printing. The creative is in the design drawing and how the computer variables are set to cause the printer to do exactly what the creator / artist desires. 

It’s very technical but if you know me, it’s right up my ally. The actual printing is the results of a lot of advance preparation. A 3D printer is simply an output tool. Same as a text printer. Both printers need the proper input before they produce text or a 3D object.

Hope you find my “time machine” creation story, interesting.

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.