In our last blog post, we went over some of the primary printing processes used in additive manufacturing. Today, we will cover why we decided to go with an FDM printing process here at Slant3D.
So hopefully this post shed some light on why we decided to use an FDM printing process here at Slant3D. The existing materials base makes it an incredibly cost-effective and convenient process. The ease of scaling up to produce hundreds, or even thousands, of parts at one time. And, the ability to pull finished parts right off the printer and ship them without having to spend hours post processing. These are just a few of the many reasons why FDM printing is the best option when it comes to mass production 3d printing, and why we have chosen this process here at Slant3D. Dont forget to check out our video on this same topic down below.
When it comes to 3d printing, there are typically 3 primary printing processes that come to mind; FDM, Resin Based, and Powder Jetting. In this blog post, we will go over the strengths and weaknesses of each of these processes.
FDM (Fused Deposition Modeling)
The biggest downside of FDM, is that it can produce parts with a somewhat rough surface finish. Because the material must be extruded in layers, and has a certain thickness predefined by the nozzle, high detail prints can be hard to achieve. However, in most cases, this roughness is so minute that it has no effect on the function of whatever you are printing. All in all, the FDM printing process remains as the most commonly used process in 3d printing, and for good reason. There aren't many 3d printing processes that are as quick, versatile, or cost-effective.
Resin Based (DLP/SLA)
Any type of resin based 3d printing, whether it be DLP (Digital Light Processing) or SLA (Stereolithography), typically all function under the same principle, using a light source to cure a liquid resin into a hardened plastic. In SLA 3d printing, a build platform is lowered into a thin layer of resin where a laser is used to draw out the first layer of the object. The laser hardens the resin and the build platform is then raised back up so a new layer of resin can be added. This process repeats until, layer by layer, the object is finished.
Resin based parts offer the highest accuracy and best resolution, in terms of surface finish. These parts will be the most similar in quality to traditional injection molded parts. The drawback of resin based printing is that it requires a lot of post-processing. Once the parts are printed they must be washed in isopropyl alcohol to remove any uncured resin from their surface. Then, the parts must go through a post-curing process to help them reach their maximum amount of strength and stability. Finally, supports must be snipped away and the remaining support marks must be sanded down to the desired surface finish. To sum up, resin based parts are great for small scale projects that require a high quality, smooth surface finish. However, it is not very conducive to mass production due to the high amount of post-processing required.
Much like resin based printing, powder jetting has many different types of processes that fall underneath it but they all work under the same basic concept. An industrial printhead selectively deposits a liquid binding agent onto a thin layer of powder. This powder then hardens and a new layer of powder is added so the printhead can deposit more binding agent and process repeats layer by layer until the object you are printing is finished. When its all said and done, your part is embedded in the powder like a fossil in the dirt. Then, you dig out your finished product, wash off the excess powder, and then put the parts through a post-curing process to strengthen them.
In conclusion, each of these printing processes have their fair share of advantages and disadvantages. Some, like FDM, are better suited for large scale production. Whereas others, like resin based, are more suited for small scale, high quality parts. Selecting the right printing process comes down to accessing the advantages and limitations of each technology to your products most important requirements. Although there is no one size fits all solution, properly utilizing 3D printing technology throughout your product's development will reduce design risk and, ultimately, result in better products.
One of the strongest qualities of 3d printing, particularly FDM 3d printing, is it's ability to take the same material, with the same properties, but make the part itself behave very differently.
For example, both products in the above image are made from the exact same material, TPU (Thermoplastic Polyurethane). They are both a 95A durometer TPU which is a fairly reasonable stiffness, about as stiff as a pencil eraser. However, when printed, the product on the left came out about the same stiffness as a pencil eraser, whereas the one on the right is much more flexible and soft (Figure B). The reason behind this is is because with 3d printing we're actually able to change the macroscopic structure of the part, thus allowing them to have very different qualities. In Figure C, you can see how the product consists of a lot of little strings stacked up on top of one another, making it very soft and flexible.
With 3d printing, we are able to vary the hardness of any parts that we print, all the way from fully solid to super flexible
and anywhere in between. This is absolutely impossible for any other machining process because this type of structure
is impossible to build with traditional Injection Molding. 3d printing gives you the ability to control the properties of the part while still using the same kind of limited inventory of materials. So no matter how odd your product may be, look into 3d printing as a way to get the exact specs that your product needs to function properly.
Generally speaking, building a print farm can be a pretty expensive investment. Starting out, you would need to buy anywhere from 10-20 machines and scale up your farm from there. But, 10 machines, at around $500 each, would result in pretty high upfront costs. So how can you get the scale of the printing farm to where you can produce 100's or even 1000's of pieces, without actually having to buy all of those machines?
Well that's why 3D printing farm services such as Slant 3D were created, so that as businesses are scaling up, instead of having to invest all that money into machines, they can just use the service to grow their customer base and be able to support those orders as they increase. Then once they hit those milestones and generate more revenue, they can then begin to buy more machines and begin printing in-house. This is a huge benefit because an internal print farm gives you much quicker control of the design, as well as, allows you to control your supply base. This limits the amount of delays and supply chain issues you may run into otherwise.
For over a century, polymers have been used in the manufacturing process to produce parts via injection moulding and 3D printing. From the initial injection moulding machines through to modern day 3D printing, the concepts have continued to progress throughout the decades to enable industries all over the world to drive production.
Since 1872, injection moulding has been used to mass manufacture a wide range of products, using a version of polymers that were specifically invented for use in the initial injection moulding machines, some of which are still in use today.
Fast forward to 1980 and Hideo Kodama filed the first 3D printing patent. His patent described a rapid prototyping system that used UV light to harden photopolymers. However, Hideo’s idea was largely overlooked, and it took until Chuck Hull patented his version 4 years later, for the real birth of 3D printing as we know it.
3D printing has initially struggled to replace injection moulding as the method of choice for manufacturers well versed with the traditional methods, until now that is! Now large scale 3D Printing farms, such as Slant 3D, are able to match injection molding on cost, speed, and scale.
To understand how 3D printing can enable mass manufacturing rather than injection moulding, it is important to understand them both and how they compare against each other.
What is injection molding (IM)?
Not long after the Industrial Revolution, American inventors John Hyatt and his brother Isaiah, enhanced the efficiency of mass production by conceptualising injection moulding. The machine used a plunger to inject melted plastic into a mould and enabled the first major manufacturing process in plastics engineering technology.
Products such as buttons and hair combs were some of the first to benefit from the birth of IM. As the technology continued to evolve, more and more industries began to benefit from it, and is still used for mass-manufacturing today.
What is 3D printing and how is it used in additive manufacturing?
In simple terms, 3D printing is the process of creating a three-dimensional solid object from a digital file.
When Photocentric began their journey in 2002, 3D printing was not at all ideal for mass manufacturing, it was expensive and proprietary, and it would take another decade before 3D printing would start to enter mainstream additive manufacturing.
Early patents started expiring and 3D printing innovation began to revolutionise manufacturing processes. At Slant 3D we have been able to develop fleets of 3D Printers are that are able to work together to reliable product 100,00's of parts at a at a time.
Examples of 3D printed products
Slant 3D's production 3D Printing Farms have enabled manufacturers from a variety of industries to deliver a wide range of 3D printed products to market, including toys, medical devices, automotive parts, PPE, stationery, industrial spare parts, figurines and many more.
As we have a team of in-house engineers, and research developers we are able to produce machines and materials to suit the requirements of numerous industrial challenges.
From prototyping to performance, Slant 3D has access to polymers to produce perfect results.
3D printing materials
Slant 3D has souced and created range of materials to suit different requirements, from flexible to castable, we have engineered materials to match the requirements of the market.
Our range covers industries such as ESD safe, aerospace, automotive, industrial, fashion and more. Each material has a unique quality, making it ideal for the individual industry.
Textures and finishes
Early 3D prints were lacking in the quality finish that was required to compete with injection moulding. However, working with software specialists, we have changed the face of additive and now offer the ability to apply almost any surface finish to a part
Enabling manufacturers to upload their own logos, textures and customer-ready finishes. The solution also offers access to more than 5,000 different texture surface structures – truly revolutionising part design and production!
Why choose 3D Printing over injection molding?
Cost comparisons between 3D printing and Injection Molding!
To imprint a diamond pattern on a flat injection molded piece can be very expensive because of the machine time it takes. However, if you choose to use an imprint of a pattern on a flat piece it may not be too complex. The mold is able to come together and stamp whatever pattern you created in the mold. Contrarily, if you are making a three dimensional object like a cube, then it becomes more difficult to manufacture. Now the mold needs to have 6 sides or more depending on your product, making it more complex.
In short, molds are expensive. However they might be worth it if your part is simple enough and you are creating thousands of products. But be sure to keep in mind that the more complicated your product is, the more expensive the injection molding process is going to be. With 3D printing, you are able to produce more complex parts with textures because it does not create an added step. With injection molding it might. So before you start to manufacture your textured part, compare the capabilities of 3D printing versus injection molding to see which is best for your company.
Small solid objects cannot be made with injection molding because the material would shrink once created. With injection molding, you would have to fill up a solid cube with melted plastic and once it starts to cool, a solid object would shrink and deform.
The sample brick made with injection molding (Figure 2) demonstrates this occurrence. You can see where the shrinkage is happening because the cube is a solid body. If you go any larger than 2 inches the shrinkage is going to be worse. This does not happen with 3D printing. 3D printing can make fully enclosed bodies that are solid all the way through.
Often when using injection molding, solid cubes are laid out flat and then molded together via heat. This process is very similar to origami; you take a two dimensional paper and then fold it to create something three dimensional. With injection molding, you create a flat mold then bring the separate pieces together to make your product three dimensional. Injection molding tries to avoid product redesigns by putting a cavity on the back side of the product. Again this still doesn’t compare to 3D printing because a fully solid cube has all six sides covered with no holes.
With injection molding, you of course have the upfront cost of the mold. This cost usually tops out at one hundred thousand dollars for the mold depending on what you're making, how complex it is, and how many pieces are in it. You may even have to get a few molds to make all the pieces for your assembly. Once you have those molds completed, the cost for raw materials for making your pieces are very low. It depends on the molder that you're working with, but very often you have a very high up front cost for the mold and then fairly low operational costs until your mold needs to be replaced.
Additionally, once the part is in production with 3D printing, you only have to take parts as you need them. You do not have to take a hundred thousand parts and ship them across the country to store in a warehouse like you do with injection molding. With 3D printing, you can produce just a hundred parts at a time and keep those around on some shelves in a back room until you sell them all, then produce another hundred and another hundred and so on. There's also the added long-term benefits when you want to change your product or make a product variation, you don't have to change your molds and do it all again. You just send a new digital file.
Some examples of 3D printed parts we have made in the past with TPU are the Flexible Robot Arm and a Headphone Earmuff. These items can take advantage of the 3D printing technology because of their material. Both products need to be able to be bent and manipulated. With 3D printing, you can make thousands of products made from rubber in a matter of weeks. There is no more waiting to make molds for rubber products.
Additionally, when you 3D print with this type of rubber, you can utilize the printing process to change how hard or soft the rubber is. The material can allow you to print items that are fairly rigid and tough with some flexibility, or objects that are soft enough to be used as padding. This is possible by altering the design of the item. The design can feature anything from thick, sturdy pieces that maintain their bendiness, or thin, thread-like layers of material that become almost cloud-like. With TPU printing, you are able to control the actual structure of the part itself down to the microscopic level.