How do we manufacture filters? | BEC Group #Automation #Manufacturing #Filters

Filters at BEC Group

Our forty years of manufacturing unique filters across household, automotive, marine and transport applications means BEC Group are well versed in producing bespoke filters for industry. We work closely with customers to understand what they are trying to protect with a filter, and how we can produce a great filtration solution.

Take a look at how we design and make a million filters every year for our customers.

Finding out about the filter

How does making your filter a reality happen? It begins with (quite a few) choice questions…

Firstly, what is it you’re trying to filter? Filtering large debris in a vacuum cleaner versus filtering impurities from liquid fuel involves completely different shapes and sizes of filter, types of media and the plastic that can be used to encapsulate it.

Once we know the medium to be filtered, we can get into the nitty gritty, asking:

  • How much space is available for the filter?
  • How will the filter be held?
  • What is the open area of the filter?
  • How permeable should the filter be?
  • How durable does the filter need to be? Can it be replaced?

The type of plastic used to encapsulate (surround and hold) your filter will depend on the environment it’s going in –typically filters are encapsulated in nylon, polypropylene, and polyester as they’re chemically stable and therefore suitable in water, oil, and air. (The mesh is usually made from nylon). In more challenging environments rubbers and TPE’s are used for their resilience.

Perfecting your filter design

After establishing the key elements of your filter, the team can then finalise its design. Most of our customers come to us with either a design or CAD of their filter. Failing this, they provide the dimensions of the space they wish the filter to fill, from either of these starting points we can begin to design the tool which will create the filter.

The next (and probably the most important) stage of the process is the design for manufacture. A DFM in a nutshell helps us to design out costs or potential problems in the design to allow for the most time and cost- efficient tool making and production. A DFM takes into account considerations for tooling, moulding and application -do you require multiple cavities to increase production speed? What wall thickness is best to make your part and cool it quickly to reduce cycle times? Will it need to filter liquids, gases, or solids? Will it be in a hot or cold environment?

Making your tool

Once your DFM and design is finalised, your mould tool can be made. Our in-house toolmakers use sophisticated CAD and CAM software and top of the range milling and CNC machines to design and cut your mould tool from a block of pre-hardened P20 steel.

Our toolmaker will keep factors such as the number of cavities required (you can make more than one filter at once if you need large quantities), plastic shrinkage, product finishes, timescales, and application all in mind when producing your tooling.


Once a tool has been made in the BEC toolroom, production can begin. The mould tool will be moved over to the filters department and into an injection moulding machine.

From here, a machinist hand loads a filter mesh onto a metal core, the steel mould tool closes around it, plastic is injected into the tool and around the filter mesh, encapsulating it in a plastic moulding to create a support frame for the filter. The filter mesh can be entirely or partially covered depending upon the filter design.

Post- production, some filters require ultrasonic welding to attach tubing to the filter or to create a strong bond between parts of the plastic framework. Others need to be assembled or trimmed. All secondary operations are carried out on site by our team.

Great quality

Key to effective, long-lasting filters is their quality. To ensure the quality of our filters are as high as possible, BEC has a full programme of quality control involving hourly visual checks, first-off and last-offs sign offs and additional checks for complex mouldings.

We are committed to continuous improvement throughout BEC, our ISO 9001:2015 certification has been held for over twenty years. As part of this accreditation, we regularly update technology and invest in new machinery to provide our customers with tooling and mouldings manufactured using the latest techniques.


Our friendly approach and impartial commercial advice to product designers, engineers and purchasing managers alike is all part of the BEC service. We work closely with you from sketches through to prototyping or from CAD to mould tooling.

We deliver filters to customers across the globe, working flexibly around their order quantities and delivery deadlines. If tight timelines are an issue, we happily part-ship orders as they’re made.

If you have a filtration project you would like our help with or any specific questions feel free to get in touch via [email protected] or call 01425 613131

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