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Utilising Additive Manufacturing for Low Volume Production
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3D Printing / Additive Manufacturing, when utilised correctly, can be the biggest game-changer for some industries. Over the past couple of years, we’ve seen a rise in supply issues due to various factors such as; COVID-19, the Suez canal closure, etc. Typically when discussing low-volume manufacturing, SLS is the leading 3D printing process due to its high-scan speeds.Â
SLS 3D Printing
What is SLS 3D printing? Selective Laser Sintering (SLS) is an additive manufacturing process that is well suited for low-volume production. Unlike other 3D printing processes, this method is a quick way of producing multiple parts in batches. This process uses a laser as an energy source which selectively melts powdered plastic material, fusing them together into a 3D printed part.Â
SLS is superior compared to other 3D printing processes thanks to its fast print speeds. Thanks to high-power lasers, scan speeds of up to 12.5 meters per second can be achieved. These faster printing speeds make it ideal for low-volume production, as you’re able to achieve repeatable results in a short space of time. Thanks to low setup costs, it’s 55-75% cheaper to produce parts compared to CNC milling.Â
Unlike cheaper 3D printing processes, for example, FDM (Fused Deposition Modelling). Parts have superior mechanical properties, similar to those of injection moulded parts. SLS 3D printed objects are isotropic and won’t deform or fail along the z-seam. Making it an ideal process for end-use, functional components.Â
TYPICAL APPLICATIONS
Parts that are best suited to 3D printed batch production runs:
- Very small parts – we specialise in really little parts, as we can get these printed much faster than larger models. We place them in and around other parts in whatever builds we currently have running, meaning you get your orders as soon as possible.Â
- Clips, mounts and fastenings – The Nylon is strong, so a great choice for your small fastenings and fixtures. Very often when producing a product in low volume it is difficult to justify spending tens of thousands on tooling for these types of items – you may find 3D printing as the ideal solution.
- Personalised items – Again, due to the lack of tooling, these are no setup costs – this means that you can make unique items for the same price as identical ones. This can be great for small corporate gifts and the like.Â
Image Credit: Formlabs
ADVANTAGES OF 3D PRINTING
- No setup fees – we don’t charge setup fees for your production runs – this means that you can order as many or as few parts as you want and not have to worry about breaking even on the setup costs or mould costs like you do in traditional manufacturing, making 3D printing a viable alternative to injection moulding and the like.
- Fast lead times – Due to the lack of tooling, you don’t have to wait weeks or months for the mould tools to be designed – simply place your order and we’ll put it in the queue. Our current record is producing 800 parts in 24 hours.
- Your prototype and final model will be identical – If you choose to prototype your model with us, you’ll be using exactly the same machines as you would with your production run, so your prototype would be exactly the same as your final model.
- Advanced post processing – At SGD 3D we offer a number of post-processing methods through our extensive supplier network. These finishes vary in quality and price, including; chemical smoothing, polishing, cerakote, electroplating, etc.
Cerakote H-140 Bright White Parts
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CASE STUDY - NETWORK RAIL
Network Rail is the UK rail networks management company. We were approached to reverse engineer a telephone base unit which was no longer supplied/manufactured. Ensuring parts were manufactured in compliance with BS EN 45545-2:2020Â &Â ISO/ASTM 52921:2013 there was no requirement for fire retardancy (UL94 classification), making SLS (Selective Laser Sintering) Nylon PA12 the ideal choice.Â
Originally manufactured using FDM (Fused Deposition Modelling), each unit took up to 52 hours to print in ABS. These units were switched to SLS (Selective Laser Sintering) where we’ve been able to achieve an average of 6 hours to print a unit. This total time saving of 156.6% is hugely beneficial to our customer, as this non-stock item is ordered on-demand and sometimes a fast turnaround is required.Â
Nylon PA12 Telephone Cradle Base Unit
SLS (Selective Laser Sintering) produces incredibly accurate parts (± 0.30 mm below 100mm / ± 0.40 % above 100mm). When mixing 3D printed parts with OEM components, this is a breeze and parts assemble without any extra reworking.Â
Image Credit: Xometry
To achieve a Black finish, parts are post-processed using a specially formulated chemical smoothing process. The benefits of this process are:
- Increased mechanical properties – removal of surface porosity and crack initiation sites
- Improved surface quality – ‘injection mould’ type finish, with a RA of less than 1 micron
- Sealed parts – air & water-tight surface, eliminating liquid and gas intake
- Reduction in bacteria growth – reduction in bacteria growth and attachment on parts
CASE STUDY - IVAN BLACK SCULPTURE
Ivan Black was born in London in 1972. His interest in sculpture began at an early age and motion quickly became central to his work, adding as he saw it another layer of complexity and interest to his experiments. An inherent problem solver, he spent his early years amassing multi-disciplinary skills in the pursuit of the means to realise his ideas.
Ivan’s current work uses his unique methodology to create forms that mutate upon the introduction of energy. The repetition of identical elements is a recurrent theme in his work, by this means he builds complex fluid structures. Each work is a section of a potentially continuous sequence, generated in form by the application of systematic rules to his geometry.
We were commissioned by Ivan to assist in the manufacture of the joint components for this structure. Originally these parts were quoted to be printed in FDM (Fused Deposition Modelling). However, we advised producing these parts in SLS (Selective Laser Sintering) due to the faster print speeds based on the volume of parts.
In total, 343 parts were printed in Nylon PA12. This material was ideal for this application due to its isotropic mechanical properties and low shrinkage.Â
Using slower traditional 3D printing methods such as FDM (Fused Deposition Modelling) would have taken up to 858 hours.
SLS is ideal for printing low-volume manufacturing jobs due to the ability to 3D pack multiple parts into our build envelope of 160 x 160 x 300mm. Parts are then printed simultaneously, taking a combined total of 243 hours to manufacture. With a total time saving of 111.7%
Image Credit: Ivan Black Sculpture
Parts required limited post-processing, and we’re media-blasted in a glass-based compound to ensure all residual powder was removed from parts and keyed ready for painting. SLS (Selective Laser Sintered) Nylon PA12 can be post-processed using a number of different methods, including; chemical smoothing, polishing, spray painting, powder coating, cerakote & electroplating.
Parts being post-processed in our material handling station
Batch of printed parts ready for dispatch
Painted & assembled
