Sarah C. Awad and Dhemerae Ford
Economic 3D Printing: How to Cut Costs on your next Project
There are three words that we never use when discussing 3D Printing: Magic, Fast, and Cheap.
3D Printing, while game changing, ground-breaking, and eye-opening, can be expensive... and very quickly, become more expensive.
With material costs for industrial machines at their current prices, combined with the amount of waste created during printing, vendors and makers alike lose a lot of money annually solely from the process. 3D Printers are also imperfect machines, in that consistent, long builds can exhaust the printers quickly without proper maintenance. Downtimes from crashes or necessary repairs also cost companies time and money in wasted materials.
The technology will get there (and it is actively getting there), but currently, other forms of manufacturing are still preferable over 3D printing for their familiarity, ability to replicate, and most importantly in their lack of dollar signs. As more people take to 3D printing as a means to create businesses, the need for bulk ordering at lower prices is increasing. While traditional manufacturing is great for large-scale orders, 3D printing shines at making small-scale, custom, or made-to-order pieces. However, if 3D printing manufactures have anything to say, that niche market is slowly and quietly changing.
Collectively, our work has been increasing in complexity and size over the years, and we completely understand the importance of these economic practices - they can make or break our dreams, and burn holes in the pockets of all of our pants!
Let us walk you through the heavy hitters in this complex conversation, and leave with you some tips, tricks, and most importantly context, under which you can potentially design a more effective strategy for your next project.
Some terminology for our newcomers to 3D printing (FYI, 101s of 3D Printing will be coming soon enough!):
Part or Model Material (Represented by the grey cross) is the plastic, powder, liquid, etc. used to construct the 3D model into your 3D print
Support Material (Represented by the blue rectangles) is the "lesser" plastic, powder, liquid, etc. that is built around (or sometimes inside) a model to protect it during the printing process. Support material is later removed and either disposed of or recycled, depending on the printer.
Shell: the walls of model that take it from being solid to being hollow- for example a PVC Pipe is a shelled cylinder.
Resolution and Printers
As we have already reviewed, the process of 3D printing involves building an object up the Z axis (vertically) by layering horizontal slices of your 3D file. Depending on the printer, these slices vary in thickness, directly affecting the amount of detail, or resolution, picked up during printing.
Obviously under this principle, thinner and more layers equal higher resolution; however, this also makes the duration of the print longer, and in 3D printing time is money. This may directly affect cost due to the extended amount of print time, so make sure to do your research on who you are printing with, for some vendors charge by printing time. It is important to note that with some printers, time does not affect cost, but nonetheless, Father Time will most likely have some cost effect, if not for you, absolutely for the vendor.
A good way to save is to print your prototypes in less expensive materials; it may not be necessary to print at the highest quality right off the bat. It is recommended, especially if you are creating a product to sell, that you always test in the final material at some point in the process, but there's no reason why your first few iterations of a new file be printed in that, especially if you're just testing for size and look. Also, printing in a lower resolution for your prototypes could cut down on price and time, which is often crucial in the initial prototyping stage.
What is probably the most dramatic way to be cost effective in 3D printing is through the width of a model's walls- the more material used, the higher the cost and longer the print time. Simply making a solid model hollow/shelled can save hundreds of dollars on printing. While seemingly straightforward, other added benefits to shelling parts include structural integrity (depending on the shell thickness and material), weight, and- depending on the material and desired look- increased translucency. It is often recommended to hollow/shell models where and when possible within reason and without compromising the integrity of the part.
Here's a Tip!
Remember your escape holes: If a closed part is shelled, an opening somewhere on the model may be necessary in order for the support material built inside to be removed. If you need one, make sure you have an escape hole at a reasonable size, and review the vendors' material guidelines for tolerances and wall thicknesses to be the most efficient.
Fill (V. Shell)
Unlike wall thickness, which is the width of the finished sides and details of the model, Fill is the material used to build the internal structure of the wall across each slice. This aspect applies more to desktop Fused Deposition Modeling (FDM) printers, when the user can toggle their options more specifically.
Many printer softwares provide options to either print with a more sparse or full coverage fill. Using a sparser fill will obviously use less material and take less time to generate, therefore reducing cost; however, depending on the model, sparser fill can weaken the integrity of the part.
Probably the most crucial of what we will talk about, the Tetris game of all this comes with several moving parts: economic orientation can be a game changer for cutting time and cost, but also plays a huge role in the strength of the model and the overall look of the final print.
The protocol is straightforward- the taller ( Z axis) and wider the model is, the longer it will take for the print head to travel about the platform, increasing time (see image).
Orientation also heavily contributes to the strength of the model. Especially for models with delicate areas like undercuts and unsupported walls, the position of the part on the platform could make or literally break them. Ideally, slices with more surface area will add strength to the part, and their direction will affect its durability to stress.
The image above shows this in action. With shorter more abruptly ending slices, the vertical standing pole will not only take more time to print, but is more likely to snap compared to its horizontal counterpart, whose longer, wider slices provide more structural integrity. The shorter height of the horizontal pole will also cut time significantly. This is one example where the strongest orientation is also the least expensive, but this will not always be the case.
IMAGE OF STRIATIONS ON PRINT
Something that can be overlooked is that the direction and placement of the slices/striations could also change the cosmetic of the final print (this is more relevant when speaking of full colored prints). If that aspect of the print is a priority, be ready to make compromises on cost and/or strength.
Tips, Tricks, and Things to Think About:
Orientation is not always guaranteed by vendors: Make sure to read their guidelines or email their customer service with inquiries. In certain situations (ie 3D Hubs), you may be able to put in a request for the parts position.
Parts that fit together must be printed in the same orientation: Due to the physical changes that result from the printing process (orientation of layers, heating, cooling, etc.), fit can be slightly to wildly affected, preventing a successful bond. As mentioned before, orientation is not guaranteed the majority of the time when printing via a vendor, but In certain situations (ie 3D Hubs), you may be able to put in a request for the parts position.
Support Material (and Orientation)
How orientation affects support material utilization
Many a time orientation and support material directly affect each other, and depending on the printer and the position of the model, can skyrocket the cost of prints. In some cases, support costs more than part material for vendors to buy (sometimes even double that of part material), and unnecessary supports built around a poorly positioned model will also produce more waste and increase the print time. You not only will pay for your print, but you may pay for the support material as well. The knowledge of knowing "best" orientation, whether printing on an at-home desktop printer or a third party vendor's machine, can be vital to understanding your print results.
Let's take a little quiz- in each example, try to decipher which orientation would be the most economic while maintaining the integrity of the model:
MODEL I: Cross
If you answered: "flat on its back," you are correct!
This cross behaves in the same way to the pole- this orientation provides the shortest print time, and the strongest layering of slices.
MODEL II: (not a real) Human Head
If you answered: "On its side," you are right again! On its side provides the shortest print time, and the strongest layering of slices.
Note: a "Bird's eye" view of the head on the print platform
This would be one instance where the cosmetic would be heavily affected by orientation; depending on how the creator wants the head to look, having long vertical striations may be distracting to the piece.
MODEL III: Whatever This Is
If you answered: "I don't know if you should even 3D print this..." you are partially right- this would be a tough print with how delicate it is!
Note: a "Bird's eye" view of Whatever This Is on the print platform
However, if this were to be printed, lying down flat would be ideal to strengthen it. It would also make it less likely of breakage during its removal from the machine.
Below are examples of different types of support generation of the same 3D model. From left to right, indicates least to most support generation. Support generation will impact your material consumption, which will impact cost. Notice how the "smart" support tried to generate less support material by creating rounded, bowed out support shapes to help keep the print stable while using less support material. Try to be aware of how the support is generated, and whether or not your model really needs to have surround support, or should have "smart" support. Not all models are fit to have smart support, like the cat above. Some models will require a heavier support style to print. It's important to understand the printer you're using for your project, and understand its limitations.
Tips, Tricks, and Things to Think About:
Toggle your support settings: If you are printing on an at-home machine, check the settings in the print software, for most printers has several ways they can generate support, some using more than others; these options can help edit it down and adjust it accordingly.
What would you add under the umbrella? Let us know in the comments below!
All of this falls under the umbrella of Design Intent, a term we're borrowing from the ideal method of design in CAD based 3D programs. Design Intent in our case, refers to the act of 3d modeling with mindfulness of your final product and how it will be produced and used - you are the chess player who makes their moves and decisions with Design Intent.
An example would be designing your part with the gap tolerances of the intended 3D printer. This could mean that you add or subtract gaps in your file to accommodate for the resolution of the 3D printer you're going to be prototyping on.
With time, iteration, and experience, the necessary skills required for designers to utilize 3D Printing will shrink, and what is even more exciting is that it is not over- this printing process itself is growing, changing, and bettering. The time of wholesale 3D printing manufacturing, cheaper production costs, and greener materials are being developed. We have a lot to look forward to.
So, keep making, keep printing, and we hope that these, tips, and tricks will keep the cost down in the meantime!