3D Printing Homework

For this assignment, students were asked to use at least two different 3D printing processes to produce an impossible object. There is a size constraint– the impossible object must fit within a given gumball capsule. For my impossible object, I chose a Mini Octopus design with articulated tentacles on Thingiverse.com.

Bambu –  Fused Deposition Modeling [FDM]

For one 3D-printing process, I chose to use the Bambu which is an FDM machine. The setup of the prints was fairly easy but I made a detrimental mistake: I forgot what I scaled my most successful print to due to the infrequent times I was available to check prints this past week mixed with having to set multiple prints at a time due to print failures.

The challenges I encountered with the Bambu printer and its software were:

• Fusing of support material and defects in object texture (potentially due to adhesion or bed-leveling issues)
• Scaling (user input error; otherwise, this function was very easy to perform in the software)

Some benefits of using the FDM production process were as follows:

• Easy set-up of prints and file manipulation
• Automatic supports and easy removal of supports (relative to following procedures)
• Fairly high-quality print; very minimal defects and visible layer separation

Overall, this process resulted in 2 well-articulated mini octopi with easily removable supports (using side cutters and fingernails) and minimal defects. I chose a scale of 70% but had to increment upwards to fill the space of the gumball capsule. Unfortunately, I had some failed prints and difficulty getting to the OEDK in between so I forgot the perfect scale I settled on (85-90%).

Formlabs – Stereolithography [SLA]

I was skeptical if this process would work for me so I started a print using a scale that I had chosen earlier in the week (70%). This print already took 14 hours so a larger scale would have taken even longer. However, to my surprise, the octopi came out very smooth with articulated joints. There were portions of the tentacles that got fused together, but the stereolithography method gave the resin a smooth finish.

These guys turned out super smooth–and cute. After placing the octopi into the Form Wash (Figure 4) and before curing (Figure 5) the printed fellas, I removed the supports with side cutters. I learned that the supports are even harder to remove after curing from classmate feedback. Overall this part of the process took 20 minutes in the wash and an hour to cure. It still took me a while (20 minutes) to remove the supports on both octopi partially because I was nervous about breaking something.

The challenges I encountered with the Formlabs SLA printer and its software were:

• Significant fusing of residual support material in small crevices after curing
• Scaling (user input error; otherwise, this function was also easy to perform in the software)
• High processing time – support removal was time-consuming and trickier than FDM

Some benefits of using the SLA production process were as follows:

• Easy set-up of prints and file manipulation
• Automatic support and auto-orientation
• High-quality print; very minimal defects (smoothest look) and no visible layer separation

Prusa – [FDM] Part 2.0

I had some difficulty using the Prusa machine since this is actually the machine I started off with but couldn’t achieve a successful print so I switched over to the Bambu printers. This process was fairly simple too– I set the scale for 100% because this is the point I misremembered/overestimated my scaling from the successful Bambu prints. These octopi were too big!! UGH. They did not fit into the capsules but I was out of time so I removed their supports and shoved them into the capsules with tape to close them (somewhat). I was pretty bummed because I ran out of time but the prints turned out great and they make for fun fidget toys.

Comparing the 3 processes and many iterations and attempts, I think the Bambu did the best job compromising on relatively even texture and fully articulated joints.  The Formlabs printer took the longest in printing and cutting supports. This print was also the least articulated out of all of them since a few of the joints fused together. The Prusa was a lower-quality print than the Bambu, in my experience, and I had to use glue on the print pad to fix my spaghetti errors. Other than those differences, I am just sad that I forgot the correct scaling causing 3 capsules to not close fully.

Cost Analysis

Cost Type	Cost	Price	Source	Quantity	Total
Materials	PLA Filament (FDM)	$19.99	Bambu Lab	1 roll	$19.99
	Grey Resin (SLA) Form 3 IPA ~ 90%	$149.00 $35.48	Formlabs Amazon	1 liter 1 gallon	$184.48
	Side (Flush) Cutters	$11.97	Home Depot	1 pair	$11.97
Labor	3D Printer Operator Prototyping Engineer	$23/hr –	Zip Recruiter Self	2 hours 2 hours	$92
	3D Model	Free	Thingiverse	0.25 hours	–
Overhead	Facility Cost (Machine Time)   Machine Cost: Formlabs Form 3+ Printer Form Wash Curing OG Prusa Printer Bambu Printer	–     $2,499 $699 $750 $1,099 $999	Machines accessed through OEDK     formlabs.com/store prusa3d.com us.store.bambulab.com	22 hours	–
	Quality Control	$21/hr	Zip Recruiter	0.5 hour	$10.5
Design	Engineering and Development (3D File)	$36/hr	Zippia	–	–
	Iterations	*	Self (Multiple Re-Prints)	2 hours	–
Misc.	Waste and Scrap	–	Supports, Skirts, and Brims; Failed Prints	–	–

* – Included in “Labor Time” Cost

Total Cost Estimate = $318.94 (borrowing equipment)

Potential Upper Limit Cost: $6, 364.94 (buying all equipment)

 

For the cost analysis, I estimate that a similar project would take about $320 to do with a 3D modeler and a 3D printing operator with the current average rates as reported by Zip Recruiter and Zippia. This price assumes that all 3D-printing machining costs and access are covered and provided by the OEDK. Buying all equipment from scratch would put this price at a whopping $6, 365 total. In this case, the model was free but someone did create it which is why I still charged the rate for a 3D model developer. If printers and tools are available, a similar project from scratch would encompass only material prices (filament and resin) and hourly rates (labor costs). This process took me some time and multiple iterations– even though the machines did most of the work, I still needed to allot time to fiddle with print settings/scale, reprint, and remove supports on the SLA prints.

Thank you so much!! 

<3 <3 <3

(Fun fact: Octopuses (the proper plural form–but I like “octopi”) have 3 hearts)