Posted on Mar 09, 2021 In News

Liquid cooling via stainless steel pipes for Laser industry

by Priatherm

Introduction

The Customer

The challenge

Priatherm’s solution

Top Challenges

Introduction

For this particular success story, we would like to talk about a challenge we faced with a company leader in the design and production of laser machines, located in Sweden.
A couple of years ago, we had the opportunity to develop the Northern European Market, since it was unexplored for us.
We always perceived the presence of opportunities for growth in these countries. We have met Swedish, Danish, Finnish companies at trade fairs, but for the material difficulty of scheduling business tours in these countries, we never went deep into it.
Why not give it a chance?
In 2018, we decided it was time to dedicate a special effort in trying to enter these markets. With a salesperson dedicated to discovering potential Leads, contact them and schedule meetings with potential customers.
Market analysis proved that, within all Scandinavia countries, the most appealing one was Sweden, given its high industrialized network around the 3 major cities Stockholm, Gothenburg, Malmö.
For that reason, we started broad research involving several sectors that could be potential customers for us:
  • Laser industry
  • Inverters for Wind and Solar Energy
  • Battery chargers
  • Industrial drives
All these applications require optimal thermal management, which for us means potential custom projects, where we can support customers from the design phase up until post-sales.
After a few weeks of researches and calls, we established the first contact with a potential customer, which allowed us to plan a visit tour at their Headquarters.

The Customer

For confidentiality reasons, this company preferred not to be directly mentioned but allowed us to talk about the project itself.
They have been involved in developing and manufacturing robotic laser systems for metalworking in the engineering industry for more than 35 years. This means they are experienced in this field, with a strong focus on dedicated R&D, and the goal of being always innovative.
They count around 30 employees and are growing at a steady rate, year after year.
The industries they serve can be divided into three main categories:
  1. Automotive – where Laser Welding can be used to weld roofs and other components; Laser cutting, for cutting of components and cutting-out of bodywork details in final production;
  2. Aerospace – Welding using lasers results in reduced weight, better fuel economy, and a smaller environmental impact;
  3. General industry – where companies contact them to solve problems related to Quality, Costs requirements, and surface finishing

The challenge

We could collaborate on a new project that started with the mechanical engineer involving us in the design of a liquid cold plate, to be inserted in a forced convection cooling system.

Its function was to cool down their tool from the radiation of a laser station.

The initial concept was based on our PT Pipe, and the particularity was the desired shape.

The customer wanted it circular, with a copper pipe based on it, and with a particular bending. But, being at the initial heatsink design phase, they were was open to different options.

After a brief feasibility analysis, our Thermal management expert gave us a positive response, and we started with an approximate heatsink design.

In the meantime, our Sales account visited the customer at their headquarter to get more detailed information about the project and to discuss deeply the alternative solutions we could propose.

This has been useful for the final customer opening to the possibility of using stainless steel pipes instead of copper pipes.

The initial customer idea

Solution

The possibility to use stainless steel pipes instead of copper pipes provided many advantages to us.

Even though copper has a better Thermal conductivity compared to stainless steel, negative points need to be mentioned:

  • Cost: copper has a higher cost than stainless steel
  • Workability: Copper is much more fragile than stainless steel
  • Impossibility of being Brazed: with Brazing technology, we can create a metal joint between the channel in the plate and the pipe itself.

Using our specific Nocolock brazing process, it’s impossible to create a metal joint between Copper (of the pipe) and aluminum (plate), because it wouldn’t reach the necessary temperature to melt both of them. The only way to fix them is to use an Epoxy resin (reducing its thermal performance).

On the other hand, brazing between a stainless steel pipe and an aluminum plate is possible. This can guarantee 100% contact between them, which can be translated into a great heat transfer.

Thus, we got a clearer idea of the possible solution and we asked for the definitive boundary conditions, in order to proceed with a Thermal simulation.

Conditions were the following:

  • 1/1.5 kW needed to be dissipated (all over the shield)
  • The flow rate is maximum 24 liters/min, but they were planning to use 7 liters/min
  • Deionized water as coolant
  • Aim for an inlet temp at 20°C deg and a hotspot on 50°C

Thermal simulation results satisfied the customer‘s request, but little details needed to be managed.

After a technical explanation about the thermal distribution, the customer was satisfied and proceeded with the Critical Design Review, a phase in which the end customer went through the design and approved it for manufacturing.

As promised, in a couple of weeks we received the Purchase Order and started the production respecting the scheduled Lead Time.

Months later, following the test phase on the Laser Machine, the customer informed us the liquid cold plate was working efficiently.

A section of the final LCP

Top challenges

  • The curved shape of the pipe – it was one of the hardest parts, but thanks to our pipes supplier, we have been able to recreate what the customer was demanding
  • Convincing the customer to change their first idea – it’s always hard to change it, but after showing the advantages our solution could offer, they accepted our suggestions
  • Maintaining steady communication over several months and being flexible – this project ran over almost 12 months, with uncertainty from the customer’s side. Despite all this, Priatherm always showed to be flexible and available for any support.

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