There is a misperception that Production 3D Printing means 100-1000 parts. Just a solution for bridging the gap between prototypes and injection molding. But this is far from the case. Mass Production 3D Printing is able to be more cost effective than injection molding beyond 100,000 pieces. And in many cases injection molding can never compare. But how is that possible. Let's go through it.
Per Part Cost
On average a single 3D Printed part is more expensive than a single injection molded part. But but by how much varies widely based on the design of the piece.
3D Printed parts can cost $0.25, $5.50, or 24.50 each. Higher volume makes them cheaper and simpler parts are lower cost to produce. This is really not that different than the per part cost of injection molding when you amortize the mold.
Now can 3D Printing ever match injection molding on price with enough volume. Yes it can. Think about the inputs. 3D Printing just needs electricity and plastic to make a finished part. Injection molding needs the same things.
At Slant 3D we have worked with many clients where the per part cost has been the same or less than injection molding into the 100,000's of parts. The higher the volume the more efficiently your part can be produced.
And a real key difference is that production 3D Printing can be profitable from the first part. Whereas molding has a large up front cost that requires the sales of thousands of units to pay off. Molding is high risk. 3D Printing is much lower risk while still being a similar or better cost.
Rarely when designing a product or looking for a manufacturer do people consider the rest of the supply chain. There is the cost to make the part and nothing else. But 3D Printing really allows for an entirely new supply chain dynamic.
With traditional manufacturing it is necessary to make a large quantity of parts in one go. And then ship and store those parts over a long period of time. Ford stores spare parts for their cars for 10-20 years. While it was cheap to mold them warehousing can account for 10-25% of the cost of a product.
A simple example would be a simple widget or toy. We will use a product from Angled.io shown below (retails for $19-25). To store this product in an Amazon warehouse would cost between $0.40-1.50 depending on the season. If they do not sell quickly then the warehousing would become about 3-5% of the cost of the product after just a few months. Imagine the carrying costs when you have to hold inventory for years.
Compare this to 3D Printing. A part only has to be made when it is ordered. Or in batches over time. There are no large production runs. This reduces warehousing to a fraction of what it was, reduces cash tied up in inventory, and ensures that supply always matches demand. While the per part cost of the part might be higher these saving often more than make up for it.
This is not always considered in monetary terms. But Risk is a big part of a product cost.
With molding you have to risk 10,000's of dollars in the cost of the mold before you can even sell your first piece. If people just don't want to buy it, then you will lose your entire investment.
3D Printing allows you to test the market. Even at very low volume (<100) you may be profitable or at least break even on each unit. And then as you grow your margins widen. But if the product doesn't sell you lose only hundreds of dollars not thousands. 3D Printing is exceptionally low risk because no part has to be made until it is sold. This is the fundamental premise of services like Angled.io
What is the cost of a delay or a shutdown. This is now known from covid, when manufacturing and shipping shut down. Local options became attractive. But even at that level traditional manufacturing is very fragile.
Most injection molding companies run 1-10 large machines making parts. If a machine breaks down, or even a operator goes home sick, a large percentage of capacity can go down and parts will be delivered late. Production 3D Printing farms are made up of hundreds of individual units. If a single one of them fails it makes no difference in production because there are ten waiting to replace one.
This makes production 3D Printing farms exceptionally reliable. Saving cost on shutdowns or delays from that single point of failure that traditional manufacturing suffers from.
So the short answer is yes, 3D Printing can produce millions of parts for the same or less cost than injection molding. Largely through the savings that it brings about up and down the supply chain from reduced risk and reduced carrying costs.
Hopefully this post has made that a bit more clear. 3D Printing is able to operate at scale without up front risk or long term shutdown issues. During the entire pandemic, Slant 3D never shut down. Our factories are too automated and efficient to require it. Our clients were able to continue to receive products instead of being caught in the limitations of overseas molding and storage.
Mass Production 3D Printing is a very affordable means of producing custom shipping trays and packaging. Since there is no molding cost, but a still a high production capacity, custom packaging solutions can be created for the same of less cost as traditional methods. And, and since it is always a custom solution the results are often better.
PCB's come in all shapes and sizes. Because of this transport can sometimes be difficult. The pieces need to be well protected (both from physical harm and ESD dangers). Very often PCB makers and chip manufactures will resort to traditional generic packaging solutions. Such as vacuum-formed plastic trays and injection molded ESD safe waffle trays.
But these have a limited viability. A chip may need special features to help with manufacturing or just a shape that works with a PCB that is outside the norm.
3D Printing can quickly create custom trays at volume without a long lead time or high expense. Generally it takes about a 1-2 weeks to complete production of several hundred trays. And depending on material the cost per chip for the packaging can be between $0.10 and $0.50, comparable to traditional solutions.
But since 3D Printing is a different process these trays need to be designed slightly differently. Here are some basic notes for your internal design teams if they are looking to design custom PCB trays. Though we also offer Design services if needed
Use Nubs or Tabs as Finding Features
Traditional designs would just have a peg with a hole to act as a finding feature when trays are stacked. This does not work with 3D Printed PCB trays because that would create an overhangin during printing. And overhang is a feature that juts at 90 degrees from a part, like the branch of a tree. Most trays are printed on end so finding pegs become that overhang.
The best alternative it to just a use small nub. This will will still prevent shifting without creating an overhang.
The other option that perfectly replaced the peg is a slot and tab. Just make certain to have the the them positioned parallel to the longest side of the tray (Again because the part will be printed with its longest side vertical on the print bed.)
Angle the Chip Slots if Overly Large
FDM 3D Printing is used to create these types of trays therefore there is a limit to how large of an bridging overhand, like the top of a chip slot, can be. generally if that upper surface is greater than 1 inch wide then this option needs to be used.
Basically, the rotate chip slots so that they no longer follow a rectangular pattern. Instead of squares they become diamonds. This eliminates the overhang and instead gives each slot a slanted roof.
This is a very simple rule. But it provides a huge advantage because it can reduce cost and improve quality at the same time. Just eliminate any sharp edge, and if a fillet can be made larger, make it larger.
Add Labeling and Branding
While 3D Printing requires some shifts in design thinking due to manufacturing limitations, there are a few things that it contributes that can vastly improve your product. Since there is no mold involved you can actually create features for free that were not even possible before. Labeling is one of those.
This labeling can be something as simple as the name of the company producing the chips, or information about the batch and chip name for us in production. An example of branding is shown below for one of our clients Silicon Mountain Contract Services
Not many trays are able to actually retain the chip in place so that it won't fall out. These features are exceptionally difficult to mold affordably. But with 3D Printing they are free to add.
Production 3D Printing can create exceptionally complex mechanisms, again without significant added cost depending on the cost. But for specialty applications systems can be created that control chips in just the right way so that they are not damaged but are released when needed in a production line. When working with Plexus we created a simple locking tab system that was able to hold the proprietary chips from the side but them lock open so that they could be removed on the factory floor.
3D Printing is very affordable and very flexible, it is an ideal way to create custom packaging solutions for PCB's or any other type of product. Why we have even done consumer packaging at times.
But the quickest way to find out if 3D Printing is right for your application is to submit a quote with your needs and specifications and one of our account engineers will be in contact with you soon.
So how is a final product manufactured with mass production 3D Printing? And more importantly what is the development process leading up to final production.
Well, there are a few steps. Mainly there to ensure that the final product is within spec for the client. Mass Production 3D Printing offers much more control and variation than traditional processes. And since it is relatively new there are areas that we think it is important that a client understand early on which can reduce cost and provide amazing new opportunities if utilized.
With this post we hope to outline the general process and why it exists, and give mass production 3D Printing clients a "look behind the curtain"
If the title is not clear enough this post focuses only on the process of mass production 3D Printing. Which is generally longer and more intensive than prototyping 3D printing. If you just need a part made quickly for testing we recommend going to our prototyping service Twist 3D Printing
Submit a 3D Model
3D Model Type
This sounds simple but can be confusing, mainly because there are dozens of 3D model formats. And what is submitted might have limitations.
When we request a 3D model we prefer a .STEP, .STL, the original CAD, or a .OBJ file. And if you are sending a zip a dimensioned drawing with critical tolerances is nice icing on the cake.
A .STEP file is the strongest because it is immediately editable, and contains accurate dimensional information. It is pretty much the universal 3D model file. And the editability is also great because we can quickly implement slight modifications that do not change the function of the part but improve its manufacturability.
Original CAD files can be converted but not always, and they can delay processing of quotes.
.STL and .OBJ are often submitted by clients with a history in 3D printing. And these files are fine. But they have no universal units associated with them and can therefore be incorrectly scaled during processing. And since they are generally files that have been developed for 3D Printing they are generally focused toward the machine or process that they were prototyped on. Which means that tolerances may be off for the mass production 3D Printing method. And last of all they are uneditable. So these standard 3D printing files are the easiest to work with but can lead to many problems.
The need for a dimensioned drawings ensures that critical features are highlighted and the tolerances associated with them. This helps during the design review.
Overall, if you can send one of each file type that is great. If you submit a .STL make sure you provide the dimensions it was created it. Or just submit a .STEP file. If you have all the files to submit place them in a zip file.
If you have none of the files requested. Send what you have and we will work through it. But do expect a delayed processing
No 3D Model
This is not uncommon. But a 3D model is required in order to 3D print the product so one must be created. Fortunately we offer a 3D modeling and engineering service, so we can create your model for you. Our team can create anything from engineering models to creative character modeling.
3D Modeling is billing at an hourly engineering rate. The advantage of our team is that they are able to optimize your part for mass production 3D Printing, speeding up the process down the line.
If you are still indeterminant about what the final production process will be, then we do recommend hiring an independent design firm. Because our team's expertise is focused on 3D Printing, therefore should that not be the ideal avenue we might not have "all the tricks" for converting your model over to something like an injection molded format optimally. We are specialists and not explicitly a design firm.
When submitting a part there is always an option to "elaborate" on it its function and specs. While it is optional, due to confidentiality reasons, we highly encourage completing it for engineering and economic reasons. The more we know about your product and what it needs to do to function, the more we can help by offering advice about optimization and good design for additive manufacturing so you get the most bang for your buck.
Any file submitted to Slant 3D is kept confidential and will not be shared outside of the organization. Any employee of the company is required to sign an Non-disclosure agreement upon hiring covrting all projects within the company that they may interact with.
That company NDA is enforced upon all employees. But we will also sign NDA's put forward by clients. If you would like to have a 3rd party NDA signed before submitting files please either contact us first or send your NDA to email@example.com
The Quote for Your Mass Production 3D Printing
Once a file is submitted to use it is forwarded one of our design engineers. These people have some of the most in depth knowledge of mass production 3D Printing in the industry. We know this because Slant 3D operates the largest 3D Printing farms in North America. Once assigned the design engineer will be with your from the beginning to the end of your project and they will be the main point of contact.
The first thing that engineer does is quote your part. This will include slicing it and receiving estimates of material use and print time. The engineer will then use their expertise to optimize the process as much as possible at this stage and give a reasonable estimate.
The design and features are then fed to our quoting system which takes into account dozens of features about the part including capacity available, lead time, rejection rate, and of course material and print time to create a final estimate.
But we do want to emphasize that we do not always agree with the final quoting system. Design of a product and the optimization of it is a process that is so broad that there can be exceptions that our automated system can't deal with. That is why the design engineer is there, and we don't use a fully automatic quoting system. A good engineer can spot things that a computer can miss. And that leads to our next component
While the engineer and system are restricted to your design when quoting they will make design suggestions when the quote is delivered. 3D Printing is a new and often foreign process so we want to make sure that clients are able to utilize our expertise in the field to get the best result. There is no reason to hire a service if that service cannot lead to a more optimal solution.
So the engineer will offer modifications that can improve price, functionality, appearance, and manufacturability. These might be as simple as reminding a client that the best way to design for FDM production is to "Minimize surface area and don't worry about volume," an idea that is counterintuitive to those with a history in injection molding, to more detailed ideas such as adding specific features. The design engineer will also have the expertise to implement those design changes if necessary.
But this part is why it is so important to provide as much information about the function and critical features of the parts at submission. Without that information the engineer is not able to make optimal suggestions quickly. It is entirely possible that they could suggest something as simple as a different material to dramatically improve the economics. But if they don't know the function of the part then they must defer to the client entirely. Because the last thing we want to do it slow the process by changing your product. But we do think it is important to make our expertise available in every way possible.
When the quote and design review are sent over to you that is the first step of what will likely be an iterative process. Ideally the client will be able to implement any design notes that the design engineer offered and have the parts requoted.
Sampling is part of the process that we consider very necessary in order to ensure that reality match expectations. Again mass production 3D Printing is quite new and we want to be certain that client are getting what they want.
A roughcut sample is a piece that has not been optimized for production. That means that it is not final and is not representative of the final product.
So why do them? Well we use roughcut samples as a quick and often free way to illustrate a challenge with the part that the client should be made aware of. For example, it may show how support material could be converted into a functional feature of the part with a redesign.
Though we are often hesitant to create roughcut samples, because clients often misconstrue them as representative of the final product, and they are not meant to be. For example, while highlighting a feature like support material usage a roughcut sample might be made with a large layer height for the sake of speed. But the client might assume that the large layer height is somehow part of the final product as well, which it most certainly isn't. So we are cautious because these quick and dirty pieces can create confusion.
Shipping Time and cost can delay a project. And often mass production 3D Printing is used to shore up a leak in the manufacturing a supply chain. Much like in the beginning of the covid-19 pandemic. So to expedite this we can do photo samples.
These pieces are production ready prints of the part which are photographed in our studio to highlight every critical feature of the part. Some include caliper measures and color comparisons.
While not the same as holding a part these samples are quite common and can create some ease of mind when a part is ordered in a rush.
Regular Sample/Production Prototype
Of course we do these. But we call them a production prototype. Therefore a fee is applied that is a prototyping fee. At this stage we go though the full optimization process. It might include several iterations on the part finding the optimal process and tweaking tolerances. This is not a push-button part of the process. Therefore it can be quite expensive. While 3D Printing is most certainly more flexible than injection molding it is incorrect to assume that there is not still a setup process for a new part or product to make it just right.
The cost of a sample is the standard setup fee, plus shipping, plus the cost of the prototype of that part at the prototype quantity. Often these will be included in the first quote you receive.
Quality Control From Samples
There is a lot of possible variation in 3D Printing. There are different processes and an infinite control of part material behavior. Depending on application there is also a broad variation of requirement from clients. A bracket might not need to look good, but a vase must be immaculate. But those words are not quantifiable. Many clients will use "good surface finish," but that phrase can have wildly different interpretations based on their backgrounds.
Therefore we have adopted the "Eye Doctor" QC method during sampling. In most cases with new clients we will send multiple iterations of the same part to the client for them to evaluate. Some will be blatantly bad, some will be "immaculate." (Particularly in the area of appearance, tolerances after all are very cut and dry. "Look good" doesn't mean anything to an engineer.) When the client receives these samples we will use their feedback to establish a QC checklist that will be used during post processing in production to verify that parts are up to spec during production. This checklist might evolve and become more narrow overtime.
Unfortunately there are not currently universal engineering standards within the additive manufacturing sector. So this has been the best method we have to ensure that we meet the clients standards when each client is different, and the technology is incompletely understood or designed for.
The quickest way to create a sample is to print it yourself and iterate until your have what you want. That eliminates shipping, and Slant 3D providing iterations to choose from. It can also be very fast since shipping and communication lags are eliminated. The reason it is not general practice is because no 3D Printer or process is created equal. And there are costs in the machine itself as well as skill of operation. We have years of experience, your company may only use it causally.
But we have fixed this problem with our Mason 3D Printer. The Mason is a prototyping machine. But one that leads directly to production with no intermediate steps. Anything made on a Mason is identical to what will come out of our 3D Printing farms. This dramatically speeds up sampling because the client can do it themselves. And if they do not have expertise in a particular area your design engineer can prepare an iteration of the part and email it you to print on your Mason. So you get our experience and one of our machines to work with in your facility or business.
Our clients who use this model often have many products (such as in a toy company) or designs which change dynamically (such as factory tooling).
Adjustment of the Quote after Sampling
As we have said the creation of the production sample is an iterative process. There is experimentation that can reveal problems with the piece that were overlooked during the digital quoting and evaluation process. Therefore after a production sample is made and evaluated the quote made need to be adjusted, either from features we find or from client feedback.
Very often the design itself will change after samples are created. And every time the design changes the quote must be updated as well.
So the part has been submitted, the design has been optimized. The Sample has been approved. Now we are ready to actually make thousands of parts and really utilize mass production 3D Printing.
The payment method and structure will be decided during the quoting process. Generally it is quoted as payment upon order if the order is under a certain dollar amount. But that is flexible based on size of the order and the structure of the contract. 50% down and Net30 are common.
Note: The setup fees are applied anytime a design is changed or a production context changes. So the setup fee is billed at sampling and at production.
We Make the Parts
Not much to say here. We make the number of parts requested with the same specs as the approved samples. We do this by using fleets of 3D Printers.
Shipping can be done a number of ways. The most common are shipping in batches, just in time, and bulk shipping.
Batches are generally the fastest way to get parts, but can increase shipping costs. But this method can allow for the payment on delivery contract that spreads out expense over a longer period of time and allows for tighter control and iteration in between shipments. Remember 3D Printing allows for a design to be changed during production without a big uproar, just a refreshed setup fee.
Just in Time is often partnered with Slant 3D's fulfillment capabilities. When an order is made we are notified though a number of means and the part is printed and shipped. This can also include warehousing of inventory or just digital inventory. This is optimal for spare parts and high margin businesses where the cost of the single part can be higher.
Bulk Shipping, is just like injection molding. We make 100,000 parts and send them to you on a pallet.
The Baker's Dozen Rule
3D Printing is new. Things are overlooked and sometimes problems can slip through. Therefore at Slant 3D we have a "Baker's Dozen Rule" where we intentionally overproduce on nearly every job to make sure that there are spares and replacements. Just in case.
We Guarantee Our Parts
Once a sample is approved and we have shipped those parts we are responsible for those parts to your doorstep. If they are damaged in transit we will replace them. If they are not up to the specs outlined and agreed upon we will replace them. A supplier should not require oversight. The reason a company uses a supplier is because they think the supplier can do the job better then they could. If we can't then it should be taken inhouse. If we screw up we own it and pay for it.
They should only be used as a last resort. That is what we would like to say to health professionals that might not be fully aware of what the technology is capable off. With this post we would like to outline the risks of using 3D printed respirator masks, both for the general public, the 3D printing community, and the medical community that might not fully understand what is being pushed by a panicked, but anxious to help, 3D printing community.
If you are using crowd-sourced masks. That is, masks that are made by local individuals with garage 3D Printers. Then you essentially have hundreds of individuals handling your masks in their homes. Those people may not be tested for Covid-19. so they could be infecting the masks that they are supplying. This means that they could potentially be directly infecting you staff if you utilize these masks. Amateur manufacturing means amateur facilities and handling.
Due to the layer lines in DIY 3D printed parts these masks can't be reliably sanitized. Therefore even though they will be relatively expensive to manufacture (2-5 dollars each). They would have to be disposable, if they can reliably be used in the first place.
The vast majority of masks printed are being printed from the baseline design in rigid materials. They do not compensate for male or female. This means that they do not fit most faces. In fact most of these masks fit little better than the oxygen mask in an airplane.
The only option to make them fit is to heat them up in boiling water or in a microwave and then press the softened plastic onto the face of the individual using the mask.
The problem is that these masks are not reusable. They cannot be sterilized. So a worker has to potentially scald their face each time they put on a disposable mask. And the seal is still not viable. Because the mask would lose its seal as soon as the healthcare worker moves their jaw.
The poor fit essentially makes the mask useless except as a splatter guard.
Again, due to the rigid materials, and DIY designs. Most of these masks do not seal around the face. Admittedly many paper masks don't perfectly seal either. But they also do not force air to move through the few crevasses that exist. And again the only way to get a reasonable fit (other than a plastic part in front of your mouth) is to heat the plastic and form it to your face.
Due to this problem healthcare professionals would almost be as protected if they simply tied a dishtowel in front of their face. Maybe better protected. (Read the full study about these materials effectiveness)
At Slant 3D we have tested every publicly available 3D Printed face mask. The one that prints the fastest is complete in 2 hours. That means that a single printer could produce 12 a day. There are only about 1.5-2 million 3D printers worldwide. That means that only 24 million masks could be manufactured per day if every printer was working on it 24/7.
China has the capability to manufacture 116 million N95 masks per day right now. And then it takes 2-5 days to ship those out. The US is expected to only need 3.5 billion masks to address coronavirus for a year. That is basically 1 month of production.
3D printing is not necessary and is not viable to address the supply shortages. Supply shortages that do not yet exist. They are only projected based on worst case scenarios. Please everyone calm down and allow the supply chains a few days to catch up.
It is truly great to see the 3D Printing community stepping up to help with local manufacturing. But respirators are not the item to manufacture. There is not yet a need, and when there is, 3D printing is not a viable solution. Please believe us we do mass manufacturing with 3D Printing for a living. Time would be much better spent on face shields, potentially ventilator parts, and general everyday aides.
To the medical community. If you have a drastic need for facemasks please use your knowledge to make a call. At this point there is no magical antibacterial 3D printing material that makes 3D printed masks much better than a torn tshirt tied across your mouth.Use your own judgement. It is possible that 3D Printed masks can help to limit the spread from covid-positive patients. But again, tshirt.
Please feel free to reach out to us here at Slant 3D if you have any questions or need to have some other part manufactured. We are standing by and reserving capacity when viable solutions become apparent.
3D Printing offers a great resource for quickly and affordably creating end of arm tooling for the many tasks that collaborative robots take on.
Collaborative robots are a great resource for smaller companies looking to automate. They are a flexible resource for completing repetitive tasks in assembly and sorting because of their flexibility and ease of training. The trouble is that robot grippers are not very versatile. Often each task needs its own specialty gripper to be created to grasp the objects in that task.
Creating these grippers is both expensive and difficult due to CAD requirements and machining costs. 3D Printing makes the creation of EOAT much easier and flexible.
End of Arm Tooling Created with 3D Printing
3D Printing is a very flexible means of manufacturing EOAT. It allows users to very quickly create custom fingers or parts nests without many machining concerns or time input. That is why Schunk has started providing resources to create custom 3D Printed end effectors. EMI has also started selling 3D Printed EOAT solutions. And there is the Slant 3D Part Mason Project that provides customisable Grippers for Collaborative robots.
Since there are so few design constraints on 3D printed parts you also don't have to worry about high costs of engineering and design bottlenecks.
How to get 3D Printed EOAT
Get a Model
At Slant 3D we maintains a team of 3D modelers that can help you design a gripper for your application within hours or days. You can also access pre-made 3D models for gripper fingers and pads at Part Mason. The models are ready immediately to be printed by a service or on your in-house 3D printer.
One other option is to use online resources such as eGrip by Schunk which can generate .STEP files that can be 3D Printed very affordably.
Print the Part
Once you have the model you can print it on your In-house 3D printed, such as the Mason. If you need higher volumes of the part to outfit an assembly line, or if you need specific material properties you can submit the design for a quote. Generally it only requires 2-4 days to turn around 100 pieces at Slant 3D.
Use Your Robot
When the parts arrive they can immediately be mounted onto your collaborative robot and put to work. If you ever need more pieces they can be ordered instantly without redesign or setup.
High Volume 3D Printing allows companies to produce products at any scale without the cost of tooling. For new companies and products this eliminates the high initial cost of tooling. And for companies making complex hardware, or low volumes of products 3D printing can allow them to access new markets faster and with far less risk.
So how is high volume 3D printing able to replace injection molding. There are a number of ways. Fast 3D printers or Lots of 3D Printers.
Fast 3D Printing
Fast 3D Printers are systems that are able to adiditvely produce parts very quickly. These are systems like HP Multi-jet Fusion (MJF) or Carbon's Digital Light Synthesis (DLS).
These technologies are able to produce parts very quickly with 3D printing. But they are limited in geometry and require a lot of post processing, so they remain quite expensive. Though when compared to the high up front cost of molding, these processes can be very useful in high margin products. The design freedom they offer with lattices and light-weighting are also big advantages.
Lots of 3D Printers (or 3D Printing Farms)
3D Printing Farms, like the ones created at Slant 3D, used hundreds or thousands of 3D printers all working in parallel to create parts very quickly at scale. A single part may take an hour to produce, but with hundreds of machines working on that part, you are now making hundreds of parts per hour.
3D Printing farms are able to achieve a much greater scale and a much better cost advantage than other systems because they take advantage of scale. They source larger amounts of more common materials and high automation eliminates the labor costs that can make other processes very expensive.
While fast 3D printing systems may only be affordable compared to molding up to about 1000 parts, 3D Printing farms have achieved cost parity with molding up to 100,000 parts. And that is just by eliminating the need for molds. Long term the savings can be even greater with better supply chain management that 3D Printing allows.
Choose the Process for your Product
It is important to understand that each manufacturing process is not a perfect substitute for any other. Each has its strengths and weaknesses. As you plan your product consider everything from design attributes to ultimate scale and production needs.
High volume 3D printing is great for getting started and scaling up. It also can provide many interesting engineering advantages. Injection molding, is great at high volumes and also provides certain engineering advantages. It is all a matter of what you product needs to be when it gets into customer's hands and your budget for making that happen.
3D Printing is an ideal means of manufacturing custom electrical enclosures.
We have worked with many industrial clients that have utilized our large format 3D printing capacity to produce electrical enclosures. The reason they prefer 3D printing is to traditional machining is primarily based on cost.
The additive nature of 3D printing reduces the amount of material needed to create an enclosure when compared to subtractive machining. After all a delrin block is far more expensive than a kilogram of ABS. Injection molding is not an option because with larger enclosures, greater than 12 inches cubed, the cost of the mold is very prohibitive. Not to mention the time to have just 10-20 enclosures produced is too long. But 3D printing can produce the pieces in 1-2 weeks.
But as is the problem with most items submitted for 3D printing, the engineer of the enclosure does not design for 3D printing. They take a traditional enclosure and expect 3D printing to create a result that is identical to other processes. It will not be. So we wanted to compile some tips for designing electrical enclosures.
Design a Foundation Layer
When printing any part a decision must be made about what side of the part will be against the print bed. Traditionally this will be the largest single flat surface. This is used to have maximum bed adhesion which limits warping and failure of parts. Generally this side is the back or bottom of the enclosure that might be mounted against a wall.
Ideally this side should have no complex features such as text. Just holes. If there is text, they it can become unreadable as the first layer is often "squashed" in order to help with adhesion.
When designing your enclosure try to create a large simple side which can serve as the foundation
If all side of an enclosure require critical details there are multiple solutions.
Printing the part with the open face down will require a longer set-up period. This orientation is difficult tp print reliably. It also requires that the enclosure be printed with support material throughout. This results in a rough interior texture and more expense, due to the support material. There is also the risk of any interior bosses or features losing detail because they printed on support material. You can see a comparison of sections of the same part printed open side down and up in the photos below.
Infill or Ribs
When a part is 3D printed there is the ability to either create a solid piece or reduce the density of thick areas of the part by using internal lattices. This "infill" reduces print time and material used and is highly recommended.
The infill makes the part behave like a sandwiched composite. So even though it uses less material it is structurally very strong at low infill percentages of less than 50%.
However if more structure is required we recommend adding ribs. These are simple to print and provide a large amount of strength. Using ribs with thin walled enclosures are ideal as they result in even less material used than infill and better control the structure of the enclosure.
Since electrical enclosures are generally purely functional, they are often printed at the lowest resolution possible. The layering is visible, but it reduces lead time and has not structural downside.
If a more refined surface is necessary the layering can be be made to nearly disappear with high resolution printing. The downside is that the printing time per part can go up as much as 300%. And the smooth surface can only be created on straight vertical surfaces. Any sort of incline or vertical curve will make the layering more visible. All of this is well defined in the part below, where it was printed with high resolution.
Reduce Rims and Overhangs
It is very common to create a rim around the top of an enclosure or case. This improves rigidity for a lid or for ejection from a mold. These rims often protrude some distance horizontally from the part with little filleting below them. This is done to reduce material used, but that is unnecessary for 3D printing (infill eliminates excess material from thick areas).
These rims in fact increase the cost and difficulty in manufacturing the part with 3D printing, because they must be supported. In the case of the part above an entire secondary structure of support material from the base of the case to the rim must be built simply to support the rim in the last 0.25 inches of the part. This adds a great amount of print time and material, therefore increasing the cost of the part.
The way to avoid this is simple to add a chamfer of fillet underneath the rim, so that it seems to gradually protrude from the case as it is grown layer by layer. Examples of this filleting are shown below.
In this particular case, the enclosure actually has an overhang angle of 90 degrees, thus requiring support. If a 45 degree chamber was adding it would greatly reduce the cost of the part.
Hopefully these pointers will help you when working on your next enclosure. When working with Slant 3D one of our engineers is always available to help you through the process. And when you submit a design for quotation we will always be willing to make recommendations in order to reduce cost.
3D Printing is a very viable manufacturing option for electrical enclosures. But to use the process effectively you must design for it. Pressing an part designed for injection molding into a 3D printer will never created an injection molded part. Better to design a part for 3D printing.