Our customer BPR Medical, based in Mansfield, Nottingham, is a perfect example of a small British company which combines expertise, creativity and entrepreneurialism to design, develop and manufacture world-beating products for export worldwide and use in the United Kingdom, for which it was rewarded in 2012 with a Queen’s Award for Enterprise: Innovation. As with any manufacturing company, the success of its products depends to a considerable degree on assembly methods.

Watch how BPR Medical found their dispensing solution

The company’s latest success story is the Bidirectional Firesafe™ Cannula Valve, used for in-home medical oxygen supplies to extinguish fires which can occur in the line between the concentrator and the user’s mask or nasal cannula. Such fires can occur if the line comes into contact with ambient flame – such as a candle – or more commonly if the patient is a smoker.

The UK’s Home Oxygen Service supports some 90,000 patients. In the US, accident & emergency units attend to in excess of 1,000 thermal burns a year caused by ignitions associated with home medical oxygen, of which smoking was by far the leading cause*.
*National Fire Protection Association estimate

Life and death integrity
BPR’s unique inline Bidirectional Firesafe Cannula Valve extinguishes the fire by cutting off the oxygen supply. It is a development of an existing, unidirectional design and acts as a thermal fuse whereby the oxygen supply is cut off when a fusible component softens as a result of the heat from an approaching fire in the oxygen delivery tube. Integrity of operation is vital and could literally represent the difference between life and death.

When BPR had chosen a two-part epoxy to bond both halves of the valve’s body, the next task was to find a dispensing solution that would assure deposition of a precise, repeatable volume of the adhesive, metered and mixed in the correct ratio, on to a cylindrical assembly. The resulting bond integrity would help ensure conformance for CE marking under European Medical Device Directive, as well as BPR’s unerring commitment to quality.

Technical Director Ben Johnson’s team evaluated a number of possibilities, including premixing and dispensing via a pinch tube valve. This yielded inconsistent results due to changes in viscosity which begin to occur naturally as soon as epoxy is mixed, exacerbated by temperature fluctuations. It also took an unacceptable amount of set-up and clean-up time.

The accuracy of volumetric dispensing
Having determined that volumetric technology would provide a better solution, BPR contacted us and two other vendors to arrange equipment demonstrations. Trials using the selected epoxy were conducted in a wide ambient temperature range, and rigorous pull, flexural and other testing of the assembled valve, revealed that the preeflow eco-DUO precision metering, mixing and dispensing system suggested by our product specialists was the correct solution. It offers ±1% dosing accuracy, >99% repeatability and can dispense volume flows of 0.2 to 32ml per minute, with a minimum volume of 0.01ml. The preeflow positive displacement technology means that the volume dispensed is not affected by viscosity changes in the material.

Key Customer Benefits were recognised as:

  • Confidence of consistently high quality
  • Increased productivity
  • Decreased operating costs
  • Time savings pre, during & post-operation
  • Reduced material usage
  • Reduced reject rates
  • De-skilled assembly process
  • Aesthetically superior products

The two alternative potential vendors and their systems were also evaluated, but we were selected – not only on the basis of the preeflow eco-DUO meeting BPR’s needs, but because of the lower total cost of ownership and promise of superior initial and ongoing support from our team.

Ben Johnson and Product Development Programme Manager Mike Brudenell worked with our product specialists to configure the dispenser into its bespoke manufacturing jig, into which the two populated halves of the Firesafe valve body are manually loaded prior to being rotated whilst the epoxy is applied. Each of the 20,000 units per month produced at the time of writing is non-destructively tested, whilst regular samples are subject to a three-point flexural test.

The system operates an automatic purge at the end of the shift, eliminating the need for cleaning down. Control is via a preeflow plug ‘n’ mix interface and stored settings ensure consistency and repeatability, and eliminate daily set-up time. Thanks to preeflow’s accuracy, the volume of epoxy applied has been reduced to 0.05g from the pinch tube valve’s 0.06g.

Ben Johnson commented:

We had to go through a number of stringent processes to ensure the integrity of the bonding of the two body halves. An essential part of this was how the two-part epoxy adhesive was applied: to ensure a highly accurate, repeatable dose on a rotating jig, but also to maintain the correct dispense volume regardless of viscosity changes caused by temperature. After evaluating a number of options, we chose the preeflow eco-DUO from Intertronics as it provided the best results for both of these criteria.

Intertronics helped us choose a volumetric dispensing solution that was the best one for our needs. We’ve been very impressed with their expertise, they’re responsive and always on hand to support us with any queries or technical support we might need. The way they’ve helped us to integrate and set up the system means that we always achieve a consistently high level of process capability.

Not only that, but we estimate our return on investment to be in the region of £2,000 a month.

Preeflow volumetric adhesive dispensing from Intertornics helps ensure integrity of life-saving medical device

The Relyon Plasma PB3 Plasmabrush offers convenient, high speed, high performance atmospheric plasma cleaning and surface activation. The PB3 Plasmabrush is a nozzle-type plasma generator which is particularly compact and offers long-term stability. Proprietary Pulsed Atmospheric Arc Technology uses a unipolar pulsed high voltage source and a vortex flow in the nozzle which delivers uniform high power density with only minimal warming of the nozzle and hardly any erosion of the electrodes.

The use of atmospheric plasmas for industrial applications has become widespread in many different sectors. Pre-treating or activation of surfaces prior to bonding, coating or laminating is readily achieved using atmospheric gases, rather than wet chemical primers. At the same time, the cleaning action of the plasma can remove residues from release agents, lubricants or cleaning agents left on surfaces. Atmospheric plasma cleaning is a dry, non-contact, non-abrasive cleaning process.

The PB3 Plasmabrush is able to be integrated into continuous production processes due to a compact and lightweight, modular design and the adaption of the PS2000 high voltage power supply to the CanOpen industrial standard communication protocol. The system supplies meaningful digital data from which valuable process information can be gained. It offers precision for fine detail areas over-complex 3D shapes and is gentle enough to treat even thin textiles or delicate materials including porous substrates and foams – large areas may be treated remarkably quickly.

The PB3 Plasmabrush is used for applications such as cleaning/activation of metals, glass and plastics for optimum wettability of coatings, inks, etc., and preparation prior to sealing or bonding. More specialised projects have included the bleaching of textiles without the use of chemicals, and plasma sterilisation of fabrics and thermally sensitive plastic materials.

Relyon Plasma PB3 Plasmabrush from Intertronics for surface treatment, activation and cleaning

The manufacture of a medical prosthetic device for a patient’s face or similar area is a highly skilled job; each one is unique, and needs to be handled with great sensitivity, as both functional and cosmetic considerations are involved. It may require careful mixing and colour matching of a silicone moulding compound, with no air entrapment, to ensure appearance and consistency of structure. Jim Dimond, Consultant Clinical Maxillofacial Prosthetist at University Hospital Coventry, explained how the Thinky ARE-250 Mixer and Degassing Machine helped move from a lengthy, manual process requiring a skilled technician, to a short, reliable and automatic mixing process.

Originally, mixing at the hospital was carried out by hand using a palette knife in two stages: mixing and then flattening on a flat glass plate to squeeze out the air. This was arduous, especially for larger quantities required for hands, breasts, facial and other components – issues equally applicable to other silicone applications such as theatrical masks, plaster casting, special effects, model engineering, animatronics, life casting and pattern making. The manual procedure was laborious and very time consuming, as it generally required use of fillers for changing consistency, and small quantities of intense colour pigment being mixed with clear silicones to suit the individual patient.

Seeking a more efficient method of mixing the compound and other components, Jim contacted our Product Specialist David Peat for a demonstration of the Thinky ARE-250 Non-contact Planetary Mixer. The Thinky process, by means of both rotation and revolution of the material, mixes and degasses at the same time. The constituents are simply measured into a container which goes straight into the machine, saving time whilst reducing material waste and clean-ups.

The Thinky solution was excellent for small quantities and also worked particularly well with their system of pre-preparing large batches of colour coded silicone – which was especially arduous and time consuming. The Thinky ARE-250 was found to easily process even highly viscous material, and once programmed ensured a thoroughly mixed, bubble-free compound to the required consistency for every batch without further intervention.

Jim commented:

I have been doing this work for about 12 years and for the past 12 months have used the Thinky a great deal. It has allowed us to quickly produce homogenous silicone in large quantities that is free of air, transforming a time consuming, physical task into an automated effortless one.

THINKY ARE-250 planetary mixer for prosthetics, mixing silicones

adhere academyWe supply a number of our adhesives and potting compounds in twinpacks. This convenient packaging offers benefits – the materials are pre-weighed in their correct mixing ratios, which saves time, and improves quality by removing the step of manually weighing out each part. Mixing within the twinpack reduces the handling of chemicals, cuts down on mess and waste, and improves the health & safety aspects of the process.

Twinpack for adhesives or potting compounds

The procedure is straightforward. Following these simple instructions will ensure that you have a fully homogeneous compound prior to use. Optimal mixing will give an optimal cure and therefore optimal performance.

The procedure is fully documented and illustrated in our free download Mixing Instructions for Twinpacks.

Mixing instructions for twinpacks

  1. Observe the Health & Safety instructions on the pack label, and any printed special mixing instructions. Wear suitable PPE.
  2. Remove the outer wrapper by cutting with scissors, taking care not to puncture the inner twinpack(s). In the case of moisture-sensitive products, it is important to inspect the outer aluminium bag before opening. If there are any holes or tears in the aluminium, do not use the pack. Bags may contain some small moisture absorbing desiccant sachets which should be discarded.
  3. Remove the twinpack, unfold, and remove the rubber end-caps from the centre clip if fitted. Grip the pack on each side of the centre clip and pull gently in a stretching motion. This will cause the clip and rail to spring off, leaving the resin and hardener together in the sachet, free to mix.
  4. Place the twinpack on a smooth, level surface and use the separator strip as a scraper, push the components from the sides and corners of the pack into the middle.
  5. Start mixing the two components by persistent hand kneading of the twinpack until the contents are uniformly blended. Take hold of the twinpack with both hands, holding your hands fairly close together and moving in a circular, scrubbing-like action.
    For twinpacks which are too small to do this, hold the twinpack against the edge of a table and scrape it back and forth.
  6. Repeat steps 4 and 5; this is particularly important with high viscosity or heavily filled systems and where there is only a small proportion of catalyst to compound ratio. Ensure all material has been pushed out of the corners of the twinpack.
  7. Mixing time will vary due to the viscosity and size of the twinpack, but normally 2-3 minutes is sufficient. Materials with very short pot life will require faster mixing. If in doubt, continue mixing as the final quality of the cured material is dependent upon complete mixing.
  8. Visually inspect the twinpack to ensure the material is thoroughly mixed, with complete uniformity and no striations.
  9. Using the clip, scrape the mixture away from a corner of the twinpack. Cut off the corner, making a large enough hole for your required rate of flow. Dispense the mixed material by squeezing the twinpack from the bottom, releasing the pressure and upending the twinpack to stop the flow.

The new Polytec PT brochure offers information on specialist epoxy resin adhesives and potting compounds for electronics, electrical engineering, optical and medical industries. It details high strength optically transparent epoxies, including formulations with flexibility in the Shore A range. Medical device manufacturers will find products which are biocompatible and tested to USP Class VI. These materials are autoclavable, a requirement when assembles are subject to repeated steam sterilising.

Typical applications for this product range include microelectronics assembly and potting; securing of lenses, prisms and sensors; bonding of fibre-optic cables; and in the medical device arena, bonding of equipment such as endoscopes where autoclaving may be required.

Both two component room temperature curing and single/dual component thermal curing types are listed to match the production processes with performance requirements.

Polytec PT epoxy adhesives enable bonding of almost any material combination – even difficult ones such as metals, plastics, glass or ceramic. Their low viscosity means that these compounds penetrate fine cracks and openings and thereby protect sensitive units against mechanical loads and the influence of most process media such as water, oil or gases.

High performance epoxy resin adhesives and potting compounds from Intertronics for specialist industries

The new Dymax BlueWave® MX-150™ LED UV Spot Curing Lamp offers the speed, consistency, reliability and long service life associated with LED UV curing. The modular unit has a separate, compact light emitter, suitable for benchtop use but small enough to be readily integrated into robotic or other fully automated systems.

The BlueWave MX-150 UV LED Spot Curing Lamp is designed to offer higher, more consistent UV curing intensities than traditional spot-curing systems – up to 40W/cm² at wavelengths of 365, 385 or 405 nm. The high curing energy is created using an LED chip in the emitter, located very close to the point of cure. The use of a lightguide, which can compromise cure intensity, is optional and the emitter can be mounted away from the controller in suitable locations and positions without loss of energy.

The BlueWave MX-150 is compatible with a variety of UV and visible light-curable materials, including adhesives, electronics encapsulants and coatings, and temporary masking products. Its instant on-off capability saves energy and eliminates the need for warm-up periods. The curing profile can be optimised to protect heat-sensitive substrates.

The BlueWave MX-150 is comprised of two main parts, a controller with an easy-to-use touchscreen interface, and the high-intensity UV LED emitter. The unit can be activated by a foot pedal, its touchscreen, or through a PLC interface.

Dymax BlueWave MX-150 high energy UV LED Spot Curing Lamp from Intertronics - for superfast cures