Custom full box build pcb assembly

“After receiving recommendations about MPE’s ability to adapt, and having already worked with us for several years, they readily approached us”

Nicola Evans, Managing Director, MPE Electronics

Wet tag production wasn’t something we’ve ever done before, here at MPE.

Equipped with our ‘can-do’ approach and mantra to prioritise client needs, our expert team, led by our Production Manager Paul Owen, leveraged their skills and industry experience to successfully rise to the challenge.

Read on for details about how we designed, set up and now consistently run a full box build wet tag assembly line with the capacity to produce 900 plus wet tag units per month for one of our key clients, a global tyre manufacturer.

Wondering what a wet tag is and what they’re used for? See our FAQs section below.

Mitigating supply chain disruption and human risk

As our client faced increasing demand from their customers to utilise wet tag sensors in their products, they needed to find and secure a dependable PCB supplier.

With rising scrutiny of and strict safety regulation in the mining industry, our client is under pressure to find ever more efficient and effective ways to ensure the safety of their tyre products. Should essential components, such as wet tags fail, the risk to their client relationship, as well as their clients’ employees’ personal safety on mine sites would be seriously compromised. Appointing a preferred supplier, able to produce wet tags to a consistently high quality standard, would be crucial to their future success.

Already working with the original designer of the wet tag technology RVL, (who was at the time the sole manufacturer), our client sought a second supplier to spread the potential risk of wet tag supply chain disruption.

“They didn’t want to put all their eggs in one basket. With increasing market demand, they needed to be sure their supply chain of wet tag sensors wouldn’t be at risk of disruption. After receiving recommendations about MPE’s ability to adapt and having already worked with us for several years, they readily approached us”

Nicola Evans, Managing Director, MPE Electronics

Can-Do’ approach

Based on our existing relationship, the client decided to partner directly with MPE for the production of the wet tags, choosing not to consider any other potential suppliers.

We immediately ran a feasibility study. Our team always adopts a ‘can-do’ approach to meeting individual client requirements. But, what we endeavour to deliver is backed up with careful planning and preparation, which is deeply rooted in our internal governance and controls. This ensures we continue to deliver to the high standard expected of us.

Our feasibility study explored space, build, equipment, processes and training from both a quality assurance and safety perspective. Once we were certain we could deliver a full box build wet tag assembly service based on these criteria, we could move ahead with the development of the manufacturing facility and the assembly line.

Our response

We place great importance on meticulously interpreting the product datasheet. We needed to establish what we could set up and produce ourselves, as well as what we needed to outsource.

Wet tag production depends heavily on using ceramic boards instead of the traditional fibreglass boards. Ceramic boards aren’t porous and won’t absorb the oil used in wet tag technology. Ceramic boards are only produced by specialist manufacturers. Knowing this, we secured an experienced supplier to provide the ceramic boards, so that we could focus on the rest of the wet tag production.

Next, we needed to consider manufacturing space. We had to guarantee enough physical space to maximise the operation of the assembly line itself. We also required room for other elements of the process, such as storage of the oil used in wet tag production. We moved all of our existing client PCB assembly to our main manufacturing facility, to reserve our secondary plant for the sole production of the wet tags.

“The secondary facility required a revamp, including the installation of benches and shelving. We also needed to build a room specifically designed to carry out the oil filling, which meant adding fireproof walls. We took care of every single detail to make sure we could hit the ground running when it came to production”

Nicola Evans, Managing Director, MPE Electronics

Equipment was another major factor in determining the success of the operation. Testing equipment, specifically radio frequency testing, antenna tuning and pressure testing, as well as the oil filling machine, and additional equipment used in the wet tag cleaning process, had to be securely installed to support optimal production.

Due to detailed planning, we were able to set up our very first wet tag assembly line in the new facility within eight months.

Foresight and planning to overcome issues

After analysing the wet tag product datasheet, we understood that the cleaning solvent required to clean the oil must not enter the drainage system. Therefore, we installed a waste tank, into which the water/solvent/oil mix is drained. In order to ensure that the tank is tamper-proof, the tank is housed in a locked metal bunded cabinet. This also prevents spillage or leaks escaping into the surrounding environment. Having found this solution, we then had to seek approval from the landlord to allow us to place the cabinet outside the factory unit.

Initially, our team was unfamiliar with oil filling; we simply hadn’t done this before. Having carefully assembled a talented and experienced team over many years, and arranging for specialist training, we were confident we could deliver.

Fast results

By the end of our first month, we produced 300 units, and in October we produced 600. We have the capacity to produce 900 plus a month. We’ve also received positive results from a recent two-day audit our client carried out, which included an in-depth examination of our processes, the product itself, our set-up, management and documentation, and ability to control our supply chain.

“The audit really put everything under the microscope and I’m proud to say we passed with flying colours. We showed the client we can do this and that we can keep on doing this reliably.”

Nicola Evans, Managing Director, MPE Electronics

“MPE’s reactivity, attention to detail, communication, engagement and commitment to quality were outstanding. They aligned [themselves] with [our] expectations and delivered products that perfectly suited our needs. They consistently went the extra mile to accommodate [us].”

Mining Services Hardware System Designer, Global tyre manufacturing client


We’re here to help

If you’re looking for a PCB supplier, ready and prepared to adapt to your specific or changing needs, please contact us at

As a team, we’re proud that we have been able to leap in and meet unit production quotas already. But what this really means is that we’ve proven to the client, ourselves, and prospective clients that they can continue to pursue ambitious growth plans when they partner with us.

Find out more about our electronics manufacturing and assembly services here.


What is a wet tag?

A wet tag is a sensor that is installed into the tyres of large haulage trucks and earth movers in the mining industry. Wet tags continuously monitor tyre pressure, temperature, and geolocation of the vehicles.

How are wet tags different from dry tags?

Wet tags are different to the original dry tag technology, owing to the oil used to ‘pot’or fill the completed electronic assembly, rather than using a solid or gelatinous compound. Electronic assemblies are typically “potted” to ensure the product is resistant to shock or vibration, and prevents water, moisture or corrosive agents from entering the assembly.

What are wet tags used for?

Wet tags can detect subtle changes in temperature and pressure, and indicate which truck and which exact tyre needs to be adjusted to meet the industry safety standard reading.

Wet tags can prolong the life of the tyre, which are costly to replace at approximately £35,000 each. They maximise productivity by decreasing unscheduled downtime. Most importantly, they play a necessary role in reducing damage to the surrounding equipment and environment, and of course, human risk.

What are the advantages of using wet tags over dry tags?

Although potted, there is a small risk that moisture can enter dry tag sensors in certain environments where extreme or rapid changes in temperatures occur. The condensation that builds up within the tyre cannot penetrate wet tag sensors, which have been specifically designed to withstand such conditions.

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