When designing a new product the best way to get an idea how it will look or feel like in the real world is to produce a prototype. A few years back this would be done in a workshop or outsourced outside of the company. This takes time and can create risk of your early designs and prototypes getting in the wrong hands. But now there is a few choices of 3D printing technology to allow to create your prototypes rapidly and some can be done in house which can save a lot of time.
The three technologies that are currently available for 3D printing are FDM (Fused Deposition Modelling) SLA (Stereolithography) and SLS (Selective laser sintering).
Let us first go into how each technology works and when they should be used in the prototyping process
FDM 3D printing technology.
FDM is the most commonly known 3D printing technology. This technology takes plastic wire and uses a motor to push it into a heated nozzle, which melts the plastic. Another set of motors drive the print head, which deposits the material layer by layer until you have a final part. This technology is the most common as it is its cheapest and cleanest form of 3D printing. No chemicals or dust is involved just plastic filament wound on a spool which feeds right into the machine which means the printer can sit in your office or on your desk.
FDM is the best technology to start your prototyping process. FDM machines can be really cheap and super easy to use. They also small enough to ft on your desk and can print different iterations out quickly. With our raspberry pi case we used FDM to create 3 Different versions each with improvements. We were able to create these versions and changed in a morning.
When we had our final design we decided to get a higher quality prototype made. This required outsourcing the process to a professional 3D printing bureau. We started with SLA
SLA 3D printing technology
SLA 3D printing is a method of 3D printing where you use a UV cured resin as the material. Either a laser or a UV projector is used to cure the resin in the profiles to create the 3D object. Resin is put in a container with a glass bottom. The platform is lowered into the resin bath and a laser or projector cures the resin in the shape of the profile to the bed. The platform moves out of the resin container allowing the area that was just cured to fill up again and the platform is lowered again.
Once the parts are complete they need to be cleaned in IPA (isopropyl alcohol). Cleaning the parts in tubs of IPA will need to be in a well ventilated area as the fumes can be hazardous. When the parts are cleaned they need to be cured further in a UV oven. This means if there is any excess resin still stuck in grooves they will cure too. Which means you can lose a lot of dimensional accuracy for engineered parts. But for organic sculptural models this technology is great for capturing the fine details. SLA requires Support structures which can scar the surface areas it is attached to, so some post production will be needed to clean this surface.
We got our parts printed on a Form 2 printer by JJ Industries. For our flat cases SLA was not the best technology. Large Flat surfaces show off all the defects and pause lines. The support struts also left marks which needed to be sanded down. This means it need to be finished and painted to make it presentable. the model was warped a little too as it still need to cure further until it gets its full rigidity. So for this type of model SLA was not the best choice. But or organic and high detailed models SLA is perfect.
We saved SLS for last as we knew this would be th best technology for this project.
SLS 3D printing Technology
SLS is a method of 3D printing where a thin layer of powdered material is deposited with a coating blade into a bin. A laser will then fill out the profile of that layer in the powder, forming a solid object. The bin will then move down the depth of the layer height and deposit more powdered material in the bin. The laser will again sinter the material on that layer as well to the layer below. The powder creates a self suspended part that requires no support. This allows you to design complex shapes.
Our SLS parts were print on an EOS P110 at 3D print UK. SLS is great for cases and enclosures as large flat areas come out clean and the layers can not be seen. It also gives a near injection mold quality. SLS can be finished very well and are great for final prototypes to present to clients.
SLS can also be used to do small batch production use. This can allow smaller business to get their product into the hands of customers with out the investment of tooling.
FDM is the best Technology to start out the prototyping phase it can be done in house on affordable machines but their quality and finish isn’t the best, unless you spend a lot of time finishing and paint the model. SLA is a technology that can create high detailed models and organic parts but their process can be long winded. You do get clean desktop machines like the Form 2 but they take longer than FDM to create quick prototypes. SLS is not a technology you would have in house as the machines are huge and can be super messy, but the quality is the best you can get. It’s easy to finish and can be polished really well. It’s the best choice for your final prototype before production.
3D printing has become a crucial part of the design process as it can give you fast prototypes and tests all the way to final prototype. It allows you to go from CAD to real life model with in a few hours. Its making the design process a faster process and allows multiple iterations to be created in a short time. It’s a tool that any design firm should invest in and can help out in any ways.