Expert Interview: Dunlop Systems and Components Mark Statham on Adopting 3D Printing for Tooling11 September 2019
Jigs, fixtures and other tooling aids form the backbone of any production floor. However, it’s not uncommon for these tools to take weeks to produce, causing bottlenecks in the production workflow.
To overcome this, companies are increasingly adopting 3D printing to speed up tooling fabrication. UK automotive manufacturing firm, Dunlop Systems and Components, is one such company.
Dunlop integrated Markforged’s composite 3D printing technology into its business at the end of 2018. Fast forward nine months, and the company is now 3D printing tooling parts and prototypes in just a few days.
In this week’s Expert Interview, Mark Statham, Production and Engineering Manager at Dunlop, joins AMFG to discuss the process of adopting 3D printing and how the technology is helping to streamline areas of the company’s production processes.
Could you tell me a bit about Dunlop Systems and Components?
Dunlop Systems was born out of the original Dunlop company in the 1960s and started out producing all types of suspension systems. This began with the mini Metro and then, progressively over the decades, we introduced air suspension onto different vehicle manufacturers’ platforms, including Land Rover, GM, Isuzu and Renault trucks, as well as specialist vehicles.
More recently, we’ve entered smaller niche markets, for example, we went into the ambulance market (Renault, LDV) and the wheelchair access market, where you have vehicles that can accommodate wheelchairs.
In 2014, we moved into a purpose-built facility and this created an opportunity to launch ourselves in new markets under the Dunlop Systems brand.
What type of customers and industries does Dunlop serve?
We mainly serve the automotive industry. For example, we manufacture vehicle suspensions for all the high-end Land Rovers, Discoveries, etc. and we do Renault and Dennis Specialist Vehicles as well.
We also serve the train industry; Bombardier is one of our customers. One of the products we produce for this sector is valves.
We do have some customers who buy our products and use them for machinery moving so they can raise machinery in the air, on an air suspension, and move it around quite easily.
Our products are also used in the industrial sector for both vibration suppression and movement. One unusual application is the use of convoluted bellows for fairground rides — so we serve a wide range of sectors.
What prompted the company’s decision to consider additive manufacturing?
Dunlop receives enquiries and interest from new customers to have our air suspension systems (ECAS) fitted to their vehicles. Customers are needing shorter lead times, from conception through to SOP, and as a result, there was a need to speed up all parts of the design and manufacturing process.
Budget constraints are quite tight because we are trying to support our customer programme without overspending. We were also trying to fund new development work to attract further new customers. So, when I was sent to look at 3D printing, it was with the thought that it would help us save money and perhaps help generate new business as well. That’s where we first entered 3D printing.
When it came to proposing the idea of additive, was it difficult to get buy-in at first, or was the whole company on board from the outset?
Engineers in our design engineering department had already had a look at 3D printing a few years prior.
We have our own test facility where we design and build suspensions and then put them on an endurance test. Obviously, these suspensions must last a million miles. They’re put on high endurance rates at high frequency and high velocity and they’re on there for about two weeks, which simulates the lifetime of the suspension unit.
When our engineers first looked at 3D printing, they found that they couldn’t achieve that sort of lifespan with the materials that were available. But we hadn’t written off the technology.
Last year, my director approached me and asked if I would participate in an online seminar to see if, and how, we could use 3D printing. The seminar, run by Markforged, showed the technology and materials they had and, more importantly, how others have used it. That’s when I thought 3D printing could be of benefit to us as well.
But to truly make a business case for it, I had to examine what parts were due for repair, what needed an overhaul, or replacing and then put a spreadsheet together with what it would cost us.
Some parts are replaced yearly, others are replaced when they break. It became clear that having a 3D printer onboard wouldn’t completely replace all the tooling because we have some high-use, high-temperature, high-impact tooling.
But it was going to provide us with the replacement option. Factoring in the costs of acquiring the printer and the monthly costs of running it, I calculated that we’d easily see the return on investment within two years.
I compiled a list of about 100 tooling parts, that I thought we could replace and that needed replacing, or that we couldn’t afford to replace. Based on that, we were able to justify the expenditure.
About three weeks later we had our printer delivered and we had the payback within six months.
What was the process of deploying the technology like in the early days?
When the 3D printer arrived, we were up and running within about an hour. We began by going through the list of our most important criteria.
We didn’t want it to run overnight at that point. We wanted to keep things simple and focus on the simple tools that were on the priority list.
For example, we have high-quality suspension items that go on high-end vehicles like Bentleys, Audis and Porsches. One of our main customers buys our modules and adds their own components to create a complete air strut.
Because these are high-quality vehicle components, we have nylon tooling to hold them in place during our process to protect the parts. These nylon tools wear out, get dirty and they’re not very attractive, so the replacement nylon parts were the first items that we printed. We replaced white nylon with Markforged’s Black Onyx.
That was well received because we were getting parts straight away within hours. Normally, if we need to replace a part, we must first find the drawing, send it out for quotation and wait for the quotation from the toolmaker to come back, which can take days.
Just getting the paperwork to raise the order took about a week to two weeks. Then for them to make the part, depending on how complex it was, could take another week.
You’re looking at a turnaround of a minimum of two weeks, whereas we were printing parts daily. That’s when our colleagues on the shop floor really saw the benefits of 3D printing.
The very first printed parts were very simple parts. Then we started going through the parts and learned how light, but at the same time how strong, the 3D-printed parts were. That opened a wide range of tooling that we could replace.
It was very well received in the first week; the shop floor was getting parts in days and hours, rather than weeks. And because we’re IATS standard, it takes longer for the quality department to inspect the part than it does for us to print it.
You said that you started off simply. Has your use of 3D printing evolved over the nine months you’ve had the 3D printer?
Yes. Now we can make very complex parts and tooling and we’ve developed methods of fixing two 3D-printed parts together.
We have a lot of small niche customers who produce wheelchair access vehicles. We have developed partnerships with these companies and part of this is to support their relatively small budgets. Other smaller customers were receiving tooling we had utilised from obsolete tools; it didn’t look attractive, but it still did the job.
Now, for those customers, we can 3D print very complex work holding parts that fit snugly to their parts and protect their parts better than before. That also means we can get the part to them more quickly, with less risk of damaging it, because it’s now a proper engineered tooling.
We’re also experimenting with different joining techniques. For example, because we mould all our products in-house, our product needs to be expanded before it goes into the moulding process.
We have an expanding machine on the shop floor which cost us about £14,000 to develop in-house. We call it “the rocket” because it’s about two metres long and it stands about two metres high. It points at an angle towards the operator, so the operator can load and unload the product quite easily from it. But the actual working area is only about half a metre long. But it’s all the actuation of that machine that makes the product expand.
For the working area, we’ve now 3D printed a half-metre tube and it’s printed in six different parts that we’ve joined together.
We’ve done the first trial of expanding a product in this half-metre tube instead of on the larger machine. But this prototype fixture is only £600, a fraction of the cost.
Because we’re now a supplier to a new automotive manufacturer, we’re likely to need about six of these machines. If this works, we can save a lot of money.
One of the things companies often tell us, is their need for AM expertise internally to be able to successfully adopt the technology. Was this an issue you faced?
We have five people in my team and our department runs and maintains the 3D printer. Everybody in our department quickly picked up on the technology and we’re trying different things.
Other departments are slowly getting used to the technology. For example, we’ve printed some gauges for our quality department. The quality department needs to check that certain parts are within tolerance. Since they’re not highly critical, we have 3D printed some gauges for them. So, our quality department has taken on board some of this 3D-printed tooling.
We’ve also produced some prototype parts for our design team. Prototype parts are normally very expensive because you must machine them from either solid steel or solid aluminium.
On a vehicle’s air suspension you normally have gaiters, which stop the stones hitting the suspension and rupturing the air bag. This gaiter is supported onto the struts using a plastic collar. Since it is a prototype, it couldn’t be moulded because nobody would design a mould for a prototype. It could have been machined from solid, but the design is so complex that it would probably take a specialised CNC machine.
As a result, we’ve 3D printed some prototype collars and, because it’s 3D printing, we can achieve the required tension because it needs to twist and move with a vehicle. That’s been quite successful.
However, when you’re looking at potentially 50,000 vehicles a year, that’s 100,000 of these products, it’s not quite in our realm of possibility yet, because we only have one printer. We’re not a 3D manufacturing company currently.
So now the design team is still looking at moulding these parts and getting a plastic moulder. 3D printing has been fine for development but it’s still a slow process.
What’s Dunlop’s vision for the technology going forward? Do you see your use of 3D printing expanding to other applications?
Currently, we are focusing on tooling because we need to completely recreate a new line of tooling within the next 12 to 18 months. We are in the process of designing this with 3D printing.
We have all the current designs, which worked well for our current line. With 3D printing, you need to do a slight conversion to make the part stronger in certain areas and we can now add carbon fibre. So that’s our focus for now.
However, because we design suspension parts from the 1960s, we still have customers who buy them. So the train industry buys our old-designed levelling valves. These are an element in body which uses a basic lever system to move air from one part of the train to the other, so that it tilts around bends. It’s used by customers like Virgin Trains and Bombardier.
This part was designed in the 1960s and early ‘70s. The original casting, which is in aluminium, is wearing out, so we’re looking at trying to refurbish that casting, which is quite expensive. But then there’s also the option of 3D printing the body for it to then utilise the system. That’s one possibility. We’ll certainly need more printers for that.
Something else we’re looking at is whether we can recycle some of our products because the moulds are getting so old.
What does the next year hold for Dunlop?
It’s going to be a very busy year for us, as we’ve got a new electric vehicle platform launch coming up. We must also support our increasing business on ECAS systems for other OEMs’ achieved IATF 16949 accreditation. Also, we will focus on the important aftermarket, which has been a long-time business model for us.
Our company focus will be on OEM high volume production, smaller aftermarket production and the further development of our industrial range of Anti Vibration components.
Regarding 3D printing, we’re overworking our 3D printer — it hasn’t stopped running. So we’re also looking to purchase a new, larger printer. That means we’ll have two printers running, which will give us more throughput.
To learn more about Dunlop Systems, visit: https://www.dunlopsystems.com/
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