The automation journey of an electrical enclosure factory

From semi-automatic produced electrical enclosures to a fully automated sheet metal bending process.

It was 2014 when a lot of skilled welders and press brake operators were nearing retirement at the nVent HOFFMAN factory in Anoka, Minnesota. It was also a time where nVent wanted to expand their business. The production process plus the products needed to be changed. Minimal manual interference and a fully automated production process for the electrical enclosures was the objective. And so it happened. Since 2016 every 40 seconds an nVent enclosure rolls off the belt.

Several high quality equipment suppliers were involved in this state-of-the-art project. For the laser welding cell and the automated sheet metal bending, nVent partnered with WEMO and AWL.

Optimizing sheet metal bending and welding  

Back in the days nVent produced the enclosures on semi-automatic lines with lots of manual operations: sheet metal bending, welding, grinding, rework etcetera.

NVent wanted to take the next step in automation in order to achieve market expansion. The production process and the products needed to be changed:

  • Going from a manual process to an automated process (less human intervention).
  • Eliminating post-processing steps that had no added value but actually were a cost item, such as grinding and re-welding. Grinding is not only a filthy and unhealthy process, it’s time consuming and labor intensive.
  • Introduction of laser welding of the enclosures which was – especially for the USA market – a great marketing tool.
  • Introduction of major flexibility; order-oriented production without downtime (automatic changeover). Incorporating customer specific requirements into the final product.
  • Safety; lean production + minimal human interference equals a minimum chance of accidents and mistakes.
  • Quality improvement; accuracy and repeatability boosts the overall product quality.
  • Output; 1 enclosure every 40 seconds!
  • Return on Investment < 3 years

Solution

For nVent, WEMO and AWL supplied a solution that produces their enclosures from sheet, all the way to the bent and welded end product.

Sheet metal bending machine for electrical enclosures

WEMO’s part in the process

The WEMO solution consists of two automated sheet metal bending machines. One line bends the body (wrapper) and the other produces the top and bottom. These 3 parts form the enclosure that is welded in the AWL laser welding cell.

The end product consists of three parts; the body (wrapper) and two end pieces (bottom end / top end). These three parts are welded together with laser welding and eventually form the enclosure.

Sheet metal bending machine for electrical enclosures

A major advantage is that the products only need to be bent lengthwise. This means that no changeovers (change in bending) are necessary during production.

To achieve the desired accuracy required for the final step in the process, laser welding, it was decided that the first step would be to laser cut the required sheets from a master sheet. This also comes with the advantage that customer-specific holes can be punched directly into the sheet.

Subsequently, a stable sheet metal bending process is required to ensure that the bends fall within the tight tolerances. The products can later be welded in one set-up without the need for post-processing.

WEMO’s swing bending process is stable and repeatable, making it the most suitable automated process for this application.

By involving AWL as a welding expert, WEMO was the total integration partner to nVent. AWL carried out welding tests on behalf of nVent and from this, the construction of the product and the required product tolerances emerged.

Sheet metal bending machine for electrical enclosures

Take a deep dive into the automation technologies

Tim Heston, Senior Editor of the trade journal The Fabricator, wrote an extensive article ‘Automation spurs a novel approach to the sheet metal enclosure’ about the project and the end result. It is an excellent article to get in-depth insights on the applied automation technologies.

How did this WEMO automated sheet metal bending line improve the business of nVent Hoffman?

For nVent there are a few key points on how it changed their manufacturing from a dominant manual to fully automated process.

  • Improved Cycle Time. nVent achieved over 75% cycle-time reduction on their key products. Moving from multiple minutes to less than a minute per finished product!
  • Ergonomics: Safety was an important factor for nVent in installing this type of equipment. Manually forming sheet metal components on a press-brake required multiple operators at times and, in some cases, was not very safe. The process now is hands-free with the WEMO automated sheet metal bending machines.
  • The quality of the output greatly improved because of the reliability of the machines and tolerance control. And it was this level of technology in bending that enabled nVent to change their welding processes into laser welding. And laser welding eliminated non-value-added processes of grinding and buffing.
  • The new technology allows nVent to gather more real-time process data. Front line supervisors have all of this at their fingertips to make decisions on production planning, workforce allocation, as well as maintenance.
  • The new equipment allows for seamless, quick changeover from one model to another. The product can be quickly changed to different customer demands and now nVent can do this many times a day without losing changeover time.
  • Costs: The operators nVent requires to run this automated line is greatly reduced but the talent level to manage systems such as these needed to be increased. This was achieved through dedicated on-site training by both WEMO and AWL.
  • With this technology shift, nVent made design changes to their product which resulted in more efficient steel utilization.

About nVent

nVent is a high-performance electrical company with a dedicated team of 9100 people and trusted brands such as nVent CADDY, ERICO, HOFFMAN, RAYCHEM, SCHROFF, and TRACER.

Known for their innovation, quality, and reliability, the products of nVent connect and protect, consistently delivering value to industrial, commercial, residential, energy, and infrastructure customers.

From heat trace cables to critical equipment enclosures to labor-efficient fastening systems, they empower customers to improve performance, lower costs and reduce downtime.

We are a very proud partner and grateful on this partnership with nVent HOFFMAN.

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