Production

Bulten has its own production of fasteners in Sweden (Hallstahammar), Germany (Berg­kamen), the USA (Hudson, from 2018), Poland (Bielsko-Biała, and from 2019 Radziechowy-Wieprz), Russia (Nizhny Novgorod) and China (Beijing).

1. Engineering

Drawings are made.

2. Tooling

All fastener parts have their own tool that is prepared before production.

3. Material

Fasteners are mainly made of steel wire using so-called cold forging technology. The iron wire is supplied as wire in rolls, usually weighing about two tons each, are transported from stock to the production area. The wire is pre-rolled, phosphated and reduced on a draw-bench down to the required dimension before being fed into the cold forger.

4. Cold Forging

After set up and control the production starts. When the wire is fed into the cold forger, it is cut to the right length and then cold forged in various steps. Cold forging is an efficient production method where between 100 and 300 fasteners are forged every minute, depending on dimensions and machine.

5. Threading

Once the fastener has been shaped, threads are formed by rotating the screw in a threading die.

6. Heat Treatment

During the heat treatment the screw is hardened to the right mechanical properties. The process starts with a washing and de-phosphating operation and then the fasteners are heated to approximately 900 degrees. Thereafter, the fasteners are cooled in oil to 60 degrees, then heated up again to 350 – 450 degrees and then finally cooled again which ends the hardening process.

7. Surface treatment

The fasteners are further processed through e.g. surface treatment and other steps to further develop the product. This is done by transporting the fasteners through a range of baths depending on the requirements.

8. Quality assurance

Besides going through continuous quality checks at each production step, the fasteners are finally checked in the laboratories and all values are documented in data bases.

9. Inspection

The fasteners are inspected for e.g. cracks, length and diameter as well as number of screws per bin.

10. Packing

After inspection, the fasteners are packed according to the customer’s requirements and then sent to the warehouse.

11. Shipping

The fasteners are ready for sending to the customer. Logistics is the final leg of our production cycle, and the final factor in our assessment of overall quality.

The fasteners are primarily made of wire rods using a cold forging technique, an efficient production method that can make up to 300 fasteners a minute depending on the machine and dimensions. The production process is the same at all plants, which means that the flexibility exists to spread production to optimize overall capacity.

 

Further refinement is taking place to an increasing extent. As well as hardening and surface treatment there are also other forms of refinement, such as lubricating coatings and assembly with washers and other parts. This is so that we can deliver a more complete, pre-assem­bled fastener, ready for direct application in vehicle assembly with no further interim stages.

One of the reasons our price structure is so competitive is that just over half of all our employ­ees are based in low-cost countries. Having plants in low-cost countries – Poland, China and Russia – as well as units in Sweden, Germany, the UK and USA, which have an important geographical proximity to our customers, creates a beneficial symbiosis which enables us to continue compet­ing for new automotive contracts while evolving the contracts we already have.
 

The environment in focus

Our environmental work strives to ensure that our production is conducted with the lowest environmental impact that is practically feasible and financially viable. All our production units have the necessary permits, and these are con­stantly being monitored. Environmental aspects are measured at each plant and reported exter­nally in line with government requirements, and also internally for collation and follow-up. Energy use is mapped locally, and the results are checked against targets and reported. Bulten is not governed by any programs for emission allowances, and does not currently work with compensation of emissions.

 

Over the next five years, we aim to halve our emissions of greenhouse gases.

 

Several of our production plants today recover surplus heat from production (e.g. from compressors and hardening) and use it to heat the premises.

Every year Bulten uses around 77,500 MWh of electricity and gas, and with our current energy mix we generate approximately 29,000 tons of carbon dioxide a year. To reduce emissions and energy consumption, we plan for instance to further increase our heat recovery, and to gradually phase out the use of fossil-based energy and replace it with renewable sources.

 

The right processes

Production systems are a vital aspect of our endeavor to be the most cost-effective manufac­turer of fasteners in the industry. Production is constantly being developed using a number of different methods, such as the internationally established 5S, LPA (Layered Process Audit), PDCA, Ishikawa, 5Why, TPM (Total Productive Maintenance), FMEA (Failure Mode Effect Analysis) and SIX Sigma, as well as our own proprietary processes.

 

Expanded production

Reliable delivery capacity is essential in winning customers’ trust, as lead times are generally so short. In 2017 we therefore made a decision to increase our capacity in Poland with a further plant, which is planned for completion in 2019. The investment in the building is worth around SEK 177 million. Heat treatment capacity will also be expanded at the Swedish plant by 25%, at an investment cost of about SEK 45 million.

 

Furthermore, we began an establishment in the USA (Hudson, Ohio) during 2017, and over four years we will invest USD 9 million in a production plant that should be ready to start production as soon as 2018.

 

Production by forecast

Production is adjusted to customers’ long-term delivery plans, and in the short term to timetabled orders that also demand precision in delivery times.

 

Head office

Bulten AB
Box 9148
400 93 Gothenburg, Sweden

Visitor's address:
August Barks gata 6A, Gothenburg
SWEDEN

Tel: + 46 31 734 59 00
Fax: + 46 31 734 59 39