Application Technology

By Peter Standring, technical secretary, Industrial Metalforming Technologies (IMfT)

Clearly, living as we do only a few decades into the Digital Age, the rapid transition from electronic calculator through computer to smartphone has rendered the statement ‘there is nothing new under the sun’ an absurdity. It is not necessary to consider how different life has become within the Digital Age, just imagine how different life would be if it all disappeared.

The importance of digitisation is not in the individual activities in which it is found – communications, finance, travel, health, legal, industry, etc, but in the kaleidoscopic variety of ways in which the core binary system can now be combined and utilised. 3D printing is a case in point where the development of computer aided design (CAD) was linked with the computer numerical control (CNC) of machines. Add material rather than removing it and additive manufacture (AM) is born.

This article is not intended to describe any of the additive manufacturing variants of the process or its background or current capabilities/limitations. These issues are addressed in numerous areas dedicated to the topic. Here, I simply wish to reflect on the wider aspects of 3D printing and the potential impact these could have on the fastener industry.

Nothing new under the sun

The concept of 3D printing is very simple. First, construct a three dimensional plan of an object and then, working from a base, split the item into a series of horizontal layers. The more layers, the finer the detail. Then program a three axis (x, y, z) machine to deposit a solidifiable material onto a base as level one and when this is able to receive the next layer, alter the z axis and print level two and so on and upwards to completion.

By printing each level only where required, it is possible to accurately produce integral voids within a printed structure which, in many cases, would be physically impossible to produce by other manufacturing methods. The nature of the materials that can be deposited and the techniques that do it are constantly being researched and developed. Currently, these include aerospace and automotive metal componentry, along with many polymer-based materials and recently, vegan synthetic steaks. CAT scan data is used to provide 3D models on which surgeons can plan/practice detailed surgery prior to an operation.

Given all of this, it is more than somewhat surprising that the concept of 3D printing evolved 4,500 years ago and its products are as visible today as they were then. It has been estimated that the Great Pyramid of Cheops at Giza in Egypt took 20,000 workers between 10 to 20 years to construct. It was built using around 2.3 million blocks of limestone and granite; layer one being a square of 230.34m in length. Blocks were not laid where chambers and passageways were required. These included two very narrow shafts (one straight the other dog legged) leading from the Central King’s Chamber through the pyramid body to the outside, one facing north the other south. The final height was 146.7m. Although, no firm evidence has yet been found to explain how such a structure was constructed what is clear and evident is that it was built layer by layer by perhaps, the world’s most spectacular and successful 3D printers?

One thing which is common to modern and ancient additive manufacturing, is the lack of fasteners in the build.

To fasten or not to fasten, that is the question

In today’s highly complex commercial world, speed to market, efficiency (however that is measured) and demand are offset by regulation, tariffs and environmental issues along with, high volumes, low inventories and slick supply chains. Introduce a pandemic and in many industrial cases, those with the highest investment in manufacture, have the most to lose. Whilst this will impact who continues to make what, perhaps the most significant effect will be the question, who designs what?

Sending goods around the world in huge container ships may be cost-effective but not needing to do this would be more so. It may be a bold claim to make but it could be argued that the ability to fasten two entirely separate items together to make something to wear, use as a tool or build a structure, was the first and most significant of mankind’s many inventions? Without this, nothing else would have been possible.

So, now we have reached a situation where many, if not most manufactured stiff or flexible goods can be produced by 3D printing. Not necessarily cost effectively or in the demanded numbers as yet but making steady progress in that direction. Consider the introduction of the automobile and aircraft. Within two decades (and a world war) both modes of transport were firmly established and locked into continuous development and improvement. Now imagine a manned base on the Moon and perhaps Mars. Clearly, as in a ship’s engine room, there would need to be some manufacturing capability with which an inconvenient failure could be prevented from becoming a disaster. Would the Space Base have a range of CNC tools to manufacture repair parts, or more likely have a suite of additive manufacturing facilities? More importantly, would the part(s) which required manufacture themselves have been designed to be produced using additive manufacturing techniques so ensuring compatibility?

This rather fanciful notion is only fanciful in 2020 but given the pending commercialisation of space and the potential, out of this world benefits which could result, such considerations become self-evident.

Designing for additive manufacturing means designs for cutting costs. Individual parts may be more expensive to produce but if they eliminate other items of inventory, which in turn require fastening together, then the cost equation becomes far easier to justify. For a rational assessment of how serious this might be for the fastener industry it is necessary to consider the areas where additive manufacturing is being used and developed.

Principles of 3D printing design

All engineers will be aware and have seen the unimaginably complex products that engineering university research teams have been producing to advertise their skills, originality and equipment for additive manufacturing. Even more impressive has been the industrial manufacturers of 3D additive parts for high-end engineering applications. Often, these are expensive structural hollow components achieving lightweighting and the required properties using additive manufacturing methods.

Metal-based products produced using powders and sintering are individual items not unlike the batch production of powder metallurgy. In a similar way, the technique of Binder Jetting is not unlike the powder metallurgy method of metal injection moulding although the products and batch sizes are quite dissimilar. In short and at present, the developers of additive manufacturing techniques are utilising methodologies that have been developed and shown to be commercially viable elsewhere. In the nano world, similar processes are being carried out on the atomic level in the products produced using graphene.

Sub micron metal powders can be produced by rapid solidification using cooling rates in the hundreds of thousands of degrees per second. These yield amorphous rather than crystalline structures providing exceptional properties. However, bonding by methods of heating will simply destroy the ‘as cast’ properties of the powders. Also, as powder metallurgy processors know only too well, handling sub micron particles adds yet another level of difficulty to what is already a difficult process route.

A major design issue in printing 3D hollow parts is to ensure that any built over voids are able to be supported until the deposited material has sufficient strength to resist sagging. Consideration of how pre-Roman builders were limited in their doorway design by the strength of the stone lintel shows the problem. This also indicates, how the development of the Roman Arch, the Gothic Arch, the use of Flying Buttresses all initially supported by scaffolding are techniques used today in the 3D printing of hollow products.

It is also possible using modern additive manufacturing methods to produce single products combining different materials. Although in its infancy, this procedure seeks to replicate the nature of multicomponent products and fabrications. Some of the components currently produced in metal, ceramic and polymer based materials can be quite large.

A life without fasteners?

Clearly, a product which is so useful and ubiquitous as a fastening device is unlikely to ever become redundant. However, if the apparently inexorable adoption of standardisation and rationalisation continues, the logical conclusion is that all things will become the same.

Standard size containers for food stuff, shipping and homes? Communication systems, clothing, transport, health care, education, all designed to cater for the increasing billions of humans living life in standard colonies/nests. As with previous spin-offs from the various space programmes, which brought in aluminium foil, teflon, heart pumps, food safety, multispectral imaging and so much more. The design and construction of non Earth based dwellings will have a similar knock-on effect on the Blue Planet. Maybe, balloon type blow up facilities will result, which are simple to erect and more important light and take minimum space to carry. Perhaps the same for inflatable, non-metal reusable food cans filled at the store? The Covid 19 pandemic has introduced the concept of foregoing individual freedoms for the common good – what about carrying this over into climate change?

The significance here is how quickly things can be made to change. The lockdown in China was no different than the lockdowns elsewhere. In the year 2000, China produced less than 2% of the world’s vehicles. Today, it is over 25%. China is at the cutting-edge of vehicle battery technology primarily because its government has the purchasing power of over 1 million vehicles each year and as part of its 5 year plan can order preferential purchases on electric vehicles. Henry Ford had the power to state: “You can have any colour so long as it’s black,” for his model T. In the future, it might be considered acceptable to declare almost anything if it is deemed to be in the cause of humanity?

Change, as we are all too well aware is inevitable and with change comes opportunity. Additive manufacturing will not happen overnight but the chaos the Covid-19 virus brought did. As a response to the shortage of personal protective equipment within the, at most risk areas, 3D printers in schools through to industry began producing their own. Automaker BMW has recently opened an additive manufacturing campus in Germany bringing training, prototyping and series production ( approximately 300,000 parts last year) as part of its global rollout of toolless production. Given BMW sold over 2.5 million vehicles in 2019, 300,000 parts is a small number now but offers significant opportunity for growth.

3D printers can develop novel products, which may combine a number of individual items into one single component thus reducing inventory and eliminating the need for fasteners. However, perhaps an equally disturbing scenario for fastener manufacturers, is the prospect of individual additive manufacturing items being produced having fastening features embedded within the design. These would interface with another part and be assembled on a – press, click, twist basis perhaps requiring a special purpose tool to ensure tamper proofing?

In short, convenience, cost and concern are likely to become the drivers of additive manufacturing uptake and the changes that brings.

Tomorrow

When nothing is certain, speculation based on prior knowledge can be useful. So, it could be useful to assess the likely drivers of additive manufacturing stated above and consider the impact they may have on the fastener industry:

Convenience: The current trend for individuals, governments and industry, is for convenience. Online activities, home/just in time deliveries, electronic payment, etc. Why buy and ship primary materials and/or products around the globe when electronic CAD data can be transferred at the speed of light. A global design house with locations geo-spaced at eight hour time zones can function 24/7. Global orders for products can be electronically distributed to regional/local additive manufacturing sites for production/assembly prior to regional/local shipment.

Cost: Speed, efficiency, easy to change, virtually unlimited energy saving features and defect-free production means additive manufacturing could become the ‘Amazon’ of manufacturing.

Concern: “It’s like herding cats,” is a phrase often used to indicate a virtually unmanageable/ungovernable situation. Despite the massive improvements made by the computerised advent of electronic purchasing portals now used throughout all supply chains, for many lower tier companies, ‘herding cats’ is an appropriate term. If the niche currently enjoyed by additive manufacturing is expanded and it becomes a dominant player, then the industrial supply chains will be radically changed and their regulation significantly simplified. Governing bodies at all levels would find such a move attractive as would the purchasing public’s appreciation over global issues such as climate change and health.

For the most part, the automobile hasn’t replaced the horse, it simply changed its role. In the same way, in the coming years, the century of oil will also transition and the role of oil will change. It is the concept of additive manufacturing that poses a real threat to fastener manufacturers because designers and original thinkers across all of industry will be considering the same questions: “How can I reduce costs, simplify manufacture and produce a better product?” If additive manufacturing becomes the snowball rolling down the slope, the tree line in its path will be significantly changed.

Conclusion

Over the last decade, applications of additive manufacturing have diversified into very low cost 3D printing kits aimed at the science toy/educational market and at the high-end, with often space related low weight/big performance products. Schools, universities, R&D labs love the technology because it offers low cost opportunities to design/produce novel output. Commercial organisations also use the technologies for prototyping show and tell ideas they wish to convey to customers or within their in-house activities.

High-end users of additive manufacturing are usually specialist technology developers/commercial entities that offer contract services or volume OEMs that see the technology as a potential major contributor to their future bottom line in cost cutting.

Although all users of additive manufacturing are seeking ways of increasing output, the current process time per machine is very slow. Of course, this is offset by the claim that other processes simply cannot produce what additive manufacturing does. So, if large quantities of products are required, then large numbers of machines are needed. The situation is not unreminiscent of the pre first Industrial Revolution where the cottage industries of spinning and weaving existed in homesteads across particular regions. If history is repeated and additive manufacturing is ‘mechanised’ and able to produce in high volumes, then the small individual commercial interests currently in additive manufacturing will find their business is reduced to a craft status.

Although many additive manufacturing user claims have been made for the process to be considered as a ‘disruptive’ technology, to date the evidence is not convincing. This is simply because additive manufacturing has not ‘as yet’ replaced whole swathes of previous products in the same way the introduction of say, the electronic calculator did for slide rules, adding machines and log tables. In this knowledge, most fastener manufacturers, can feel secure for now. However, they should perhaps be warier of the loss of product variety and consequent business opportunities brought about by the seemingly inexorable drive for standardisation, rationalisation and regulation. If additive manufacturing could turn these juggernauts round, then it truly would be considered disruptive.