When to Use ESD-Safe 3D Printing

Written by Senior Application Engineer Benjamin MacDonald

ESD-safe 3D printing materials that boast the high temperature, high resolution and scalability are hard to come by. While there are some extrusion-based options available, these often don’t meet the requirements for production applications as the throughput is low and surface finish is poor. Fortify’s recent announcement of our ESD-HT (high temperature) material allows for the mechanical and electrostatic discharge properties required with all the added benefits of a DLP powered system. 

Two key properties of ESD-HT, Fortify’s ESD-safe 3D printing material is its HDT of 284C and its stiffness of 5.3GPa. 

Combining these materials properties with the ease of manufacturing that FLUX Series printers enable, there are a range of exciting applications where 3D printing can help electronics manufacturers save time and money.

In this blog we will explore some of the applications for ESD-Safe 3D printing including: solder reflow trays, SMT pick and place nozzles, PCB quality testing, and magnetic data storage Protection. Below we dive into these applications and why Fortify’s ESD-HT is uniquely suited for success. 

Solder Reflow Trays

What it is:

Solder reflow is a specific soldering process used mainly for surface mount components. It is an efficient way to quickly solder a large quantity of components to a circuit board and the process can be fully automated. At a high level the process can be broken down into three main steps; laying solder paste, placing components, and the reflow process. Out of the three discrete steps, the most environmentally challenging step by far is the actual reflow process. The reflow process consists of heating the PCB’s to temperatures of up to 250C+ in order to melt the solder paste and join the component to the board. This is done in a reflow oven where boards are exposed to these temperatures for significant periods of time. One key area of concern during this process is ESD safety. Temperature change is a very easy way to generate a static charge and as a result it is highly important to ensure that PCB’s are properly protected.

Challenges with traditional manufacturing:

Today these reflow trays are typically machined out of a few different materials that are all able to withstand the temperature requirements of a reflow oven while remaining dissipative. While these materials are able to function well, they are very difficult to machine and stock material is expensive. Being specialty materials, it can be difficult to find someone to reliably machine them and lead times typically are a number of weeks. All of this effort goes towards a manufacturing aid that ultimately is useless when the production of a given product is complete.

Solution with ESD-Safe 3D printing

This application was practically made for Fortify’s ESD-HT; a material that maintains its rigidity up to 284C while avoiding all of the typical pitfalls associated with traditional manufacturing. Leveraging a Flux Series printer, users are able to print these reflow trays in a matter of hours rather than weeks meaning that PCB’s can go into production significantly faster. Due to its dissipative resistivity, PCB manufacturers have the peace of mind that their boards won’t be damaged during the reflow process. 

SMT Pick & Place Nozzles

What it is:

Surface Mount Technology or SMT is a process that places electrical components onto a PCB prior to that PCB entering a reflow oven. SMT is an automated process that compared to manual component placement processes enables more precision for the components location and a much higher packing density of components. This means that boards can get smaller while still holding the same number of components. On top of this, SMT is an extremely fast process allowing for thousands of components to be placed every hour. The process is a vacuum based process that pulls a vacuum through a nozzle to pick up components and releases the vacuum when the component is in place. SMT is a very popular method for PCB production due to its speed, accuracy, and efficiency.

Challenges with traditional manufacturing:

Today these nozzles are mainly manufactured out of steel and outfitted with ESD safe tips which is great for durability but not ideal for ease of manufacturing. Since these tips have to pull a vacuum, manufacturers need to machine in a vacuum channel. The components that these nozzles need to pick up are typically very small meaning that these channels also need to be very small. This leads to a common challenge in the machining world, accurately drilling small diameter holes. These drill bits are very prone to breaking and if they don’t break keeping a hole straight is a whole other challenge.

Solution with ESD-Safe 3D printing:

The easiest way to drill these holes is to simply not drill them at all. With ESD-HT users can just print these tiny holes rather than dealing with the headaches of trying to drill them. Nozzles printed with ESD-HT have the ability to resolve holes that are smaller than 0.8m in diameter (a typical size for nozzles) while maintaining the necessary stiffness to accurately pick and place components in their target locations. In a matter of hours these nozzles can be printed and in a SMT pick and place machine laying out components on circuit boards.

PCB Quality Testing

What it is:

Most PCBs will undergo quality testing to verify that the PCB will function as intended. This can vary from a simple optical inspection to verify component placement, to rigorous environmental testing to ensure that the PCB will function regardless of the heat, humidity, or mechanical shock that it may be exposed to. Throughout all of this testing, PCBs need to be safely fixtured to avoid any unwanted ESD events. this fixturing is done most commonly with a PCB rack.

PCB racks are great for efficiently testing a large number of PCBs at once as they enable very tight packing of the circuit boards into a small footprint. These racks excel for production scale testing and are easily sourced from a variety of suppliers. 

Challenges with traditional manufacturing:

The two main drawbacks of  these racks are that they can be expensive and they are not easily customizable. The way the PCB industry is headed (higher mix, lower volume) this makes it more difficult to justify purchasing an expensive rack that might only be used a handful of times before it is no longer needed. Pair this with the fact that more and more circuit boards are unique designs with custom geometries, it makes less sense to try to implement a one size fits all solution.

The Solution with ESD-Safe 3D Printing:

Enter ESD-HT. With ESD-HT contract manufacturers are able to design custom racks that precisely fit each circuit board. Leveraging the speed of additive manufacturing, contract manufacturers are able to print these custom racks in a matter of hours rather than waiting a days for a standard rack to arrive. By designing these racks for the exact product a CM needs, they are able to use less material than traditional methods, resulting in  less waste and greater cost savings. The economics behind esd-safe 3D printing make sense but more importantly the performance does not suffer with ESD-HT.. With an HDT of 284C, ESD-HT is able to withstand the thermal loads of up to 200C that are seen during thermal shock testing. ESD-HT is dissipative in nature so circuit boards are fully protected from an ESD event that can easily occur due to the drastic change in temperatures during testing. This is just one example of environmental testing that is done on PCBs. Regardless of  what testing needs to be done on a given circuit board, ESD-HT is fully capable of safely fixturing boards so that testing can proceed efficiently.

Magnetic Data Storage Protection

What it is:

Magnetic data storage is one of a few different ways that data is stored today. Data is stored on a magnetic medium using different magnetisation patterns to represent the given information. It is one of the cheapest ways to store data, and as a result it is used in most computer systems as the main data storage. Even though it isn’t the highest performing data storage method, the  economics behind this solution make it widely used and is  here to stay. Historically, some of the most common uses of magnetic data storage were in floppy disks and the magnetic credit card strip. Today the most common use is a Hard Disk Drive (HDD).

One of the key drawbacks of magnetic data storage is that it is very susceptible to ESD events which can alter or corrupt any data that is stored. This means that it is important to have good ESD protection surrounding the storage device, otherwise all of the data is at risk. 

Challenges with traditional manufacturing:

Fortunately for HDDs, there are very robust thermoplastics available to injection mold housings for these drives. Unfortunately, the economics of these housings only make sense at volume. It can be tough to justify the cost of an injection mold tool just to mold a few housings, and product testers certainly can’t forgo a robust ESD safe housing. Another option would be to machine these housings out of an ESD safe plastic but the lead times would significantly impact the product development timeline. Using an existing housing would work but designing the device to an existing footprint severely limits the ability for innovation. Regardless of what option is chosen, none feel like a truly good solution.

The Solution with ESD-Safe 3D Printing

This is exactly the scenario that ESD-HT was made for. The dissipation of ESD-HT gives designers the peace of mind that their HDDs will not be damaged from an ESD event. Pair that with a high stiffness to physically protect the HDD, and ESD-HT is the right material for the job. Even though ESD-HT has great performance, what separates ESD-HT from traditional manufacturing methods is the barrier to entry. Using the HDD example, a handful of housings would cost thousands to be manufactured via injection molding. Depending on the housing size they would cost $10s to $100s in materials to be printed on the Fortify platform. To machine these housings would take days or even weeks, but with a Fortify machine they can be printed in a matter of hours. The key is that each housing is fully customizable so it can be designed to best fit an HDD, rather than having to design an HDD to fit into the housing. With all of these benefits it’s easy to see that prototyping these housings in ESD-HT can save time and money, and even bolster innovation.

Conclusion

PCB environmental testing and magnetic data storage are just two additional ways  ESD-HT can be leveraged to further improve ESD safety. Fortify is  always looking for new and exciting applications for ESD-HT as well as our other materials, and  our favorite way to validate new use cases is through collaboration.If this sounds interesting, check out our benchmarking service,  which we provide free of charge to help get functional parts in your hands as seamlessly as possible. Alternatively, if you want to test out ESD-HT for yourself before diving into an application, we offer a variety of sample parts in ESD-HT, available for free upon request. . 

 

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