Epoxy Resin Injection Pump for Mould Filling

In our latest case study, we are drilling down into a project we worked on for a client who needed an epoxy resin injection pump for mould filling.

The company were planning to fill small moulds with resin to manufacture test pieces before going into production, using a process known as resin transfer moulding or RTM. 

What is resin transfer moulding?

This is a highly effective low-pressure moulding process used to produce fibre plastic composite parts with high levels of strength and durability. 

The method involves injecting a mixture of resin and catalyst into a closed mould containing dry, semi-finished fibre parts in a preform or fibre pack. 

The fluid impregnates all of the fibres under pressure, and the finished part sets and hardens within the mould. When the resin has cured, the mould is opened and the finished component can be taken out.

The process is extremely flexible and offers a wide range of resin systems including epoxy, phenolic and methyl methacylates, vinylester and polyester, combined with pigments and fillers including calcium carbonates and aluminium trihydrates if needed.

In addition, the fibre pack can be glass, carbon, aramid (also known as Kevlar), and even some organic fibres like hemp, or any combination of these materials in a wide selection of weights and styles.

What are the advantages?

• Automated process

RTM can be fully automated helping to raise production rates and lower labour costs 

• Complex shapes

RTM can easily mould parts with complicated designs, making it suitable for many applications where other production processes might struggle

• Tight tolerances

RTM produces exceptionally precise parts with very accurate dimensions, which is important in applications where closely fitting parts is essential 

• Low material waste

Closed moulds and near-net-shape mouldings produce components close to their final size and shape, reducing waste and removing the need for further machining

• Tooling flexibility

RTM tooling is inexpensive compared to other production processes, yet it can still be used to make an enormous range of parts 

• High-quality finish

Parts produced by RTM have a smooth finished surface so there’s no need for any trimming or sanding 

• Cost-effective

RTM is a great option when making medium to high volumes of parts, especially compared to processes like hand lay-up or autoclave curing

• Strong, lightweight parts

By incorporating fibres, RTM produces parts that are light, robust and durable, making it a good choice for applications where weight is a critical factor 

• Low emissions

RTM uses closed moulds so it produces far fewer volatile emissions than open mould production methods like spray-up or hand lay-up

What the client needed

For this specific application, the client was manufacturing pieces the size of a 32” TV, - around 42cm by 59.4cm. Our peristaltic metering pump would be lifting the mixture from a heated resin pot under vacuum, to ensure that all of the air was removed before the mixture was transferred to the mould.

The liquids being pumped could be up to 80°c, and the pump needed to be variable speed to produce enough pressure to fill the required shape, but not excessive pressure which might distort the fibre preform.

Our client was a start-up business which was just beginning to manufacture on a small scale. It was essential therefore that the pump was easy to use and could be powered by domestic mains.

In addition, it was important that the peristaltic pump could be reversed if required, and that the pump hose could be cleaned easily and changed quickly between batches.

What we specified

At North Ridge Pumps, there are no restrictions on the type of pumps we can specify, we’re not tied down to any one pump type or technology.

As the UK’s biggest pump supplier with over 25 years in the business, we’re experts at specifying pumps for a huge range of applications.

We use our specialist knowledge to craft the best solution for every client, not just a standard product picked off the shelf. In fact, we select the most appropriate pump for every project brief offering the best long-term option.

One of our smallest pumps

For this specific project, we selected one of our Boyser DS-M peristaltic dosing pumps, our smallest peristaltic pump series. These hardworking pumps are specifically designed for dosing or transferring fluids at low rates of flow and at operating pressures up to 2 bar.

Very popular within the chemical and food industries, these units have a neat, compact design whilst still being surprisingly powerful and able to achieve a discharge head of 20 metres.

Reliability and flexibility

The whole DS-M range has been purposely designed for non-stop operation and outstanding reliability. They are self-priming and can pump liquids even containing small solids or particles. In addition, they are just as adept at pumping fluids in a liquid state that also contain vapours, gases or air.

The range offers flexibility too with six different tube diameters available which are interchangeable between the 18 different pump sizes and configurations which can be specified.

All of the DS-M range are fitted with a triple rotor comprising three rollers as standard. This innovative design feature makes the DS-M pumps very accurate and able to keep flow pulsations to an absolute minimum.

A wide range of applications

• Chemicals

Doses a range of liquids including resins, latex, glues, oils, colorants, dyes, acids, pigments, defoamers and so on

• Food and beverages

Doses additives in breads and pastries, juices, sauces, syrup, lactic ferments, colourants, enzymes and beverages

• Water treatment

Feeds filtering membranes, doses chemical products like polymers, ferric chloride, ferric sulphate, sodium hypochlorite, doses media with suspended solids such as activated carbon, potassium permanganate, lime slurry and more, plus water sampling

Other sectors

Agriculture, engineering, mining, pharmaceuticals and laboratories, paper, printing and packaging, ceramics and more

The model we specified from the range: the Boyser DS-M/Lab hose pump

From the DS-M range, we selected the DS-M/Lab, a small peristaltic metering pump. It is the ideal option for a low flow, small scale application like this and many other laboratory and pharmaceutical uses including:

• Processing

Precise drug flow control, chemical engineering and injection, corrosive liquid transfer, laboratory reagent and buffer distribution, and sampling

• Microbiology laboratories

Distribution of culture media, buffers, diluents and a variety of sterile solutions

• Medical and biotech

Infusion, dialysis, extracorporeal circulation and high-purity liquid analysis

Featuring a quick hose replacement pump head, it has been specially designed for applications where easy and quick hose replacement is vital, without operators needing any tools or training. To replace the hose simply:

1. Close the valve of the feeding chemical

2. Push the grey hose holding clips apart and release the pump head

3. Pull out the hose and replace

4. Press the clips together on the pump head

It is also self-priming, works on a single-phase power supply and can run dry without damage.

The Boyser DS-M/Lab pharmaceutical peristaltic pump enables users to ensure full traceability and guaranteed results, as one tube is used per chemical, mixture, flavour or dye.

In addition, the client requested that the pump could be reversed if necessary. So this pump has a built-in inverter which allows operators to speed up, slow down or reverse the unit if required.

If you have an application requiring the transfer, circulation or injection of fluids and are looking for an easy-to-maintain solution, speak to North Ridge Pumps to see how we can help.