Nordson_EFD_Medical_Device_Assembly_White_Paper.pdf

Published by: Nordson EFD LLC, 40 Catamore Boulevard, East Providence, Rhode Island 02914-1206 10 Essential Questions for Reevaluating Your Medical Device Assembly Process Thank you for your interest in Nordson EFD’s Dis…

Published by:

Nordson EFD LLC, 40 Catamore Boulevard, East Providence, Rhode Island 02914-1206

10 Essential Questions for

Reevaluating Your

Medical Device Assembly Process

Thank you for your interest in Nordson EFD’s Dispensing Solutions.

For a confidential discussion of how we can help you improve your

medical device dispensing systems, we invite you to contact our

experienced Product Application Specialists at 800.556.3484 or

info@nordsonefd.com.

Medical device manufacturers that assemble devices and equipment must meet stringent

FDA regulations for quality and product consistency, which makes rigorous process control

essential. Fluids for medical device manufacturing can be extremely expensive. It is vital to

have quality assembly equipment that generates consistent and accurate results, without

fluid contamination, to avoid costly waste.

Is your current dispense valve system giving you accurate deposits with minimal

maintenance – or are you applying inconsistent amounts of fluid and wasting too much

time and money on downtime, rework, and cleanup?

This paper discusses some common problems encountered with typical fluid dispensing

systems in the medical device industry, and offers helpful tips for improving your dispense

valve performance.

We hope that you find this information helpful. If we can be of further assistance,

please contact our experienced Product Application Specialists at 800-556-3484

or info@nordsonefd.com.

Is Your Medical Device Dispense Valve System Delivering

All The Performance You Paid For?

www.nordsonefd.com 2

1. Are You Using the Best Dispense Valve for Your

Fluid Application?

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For most medical device dispensing applications, a well-designed, general-purpose

diaphragm or piston valve that can handle a range of fluid viscosities is a good

choice.

In most situations, however, best results will be obtained with a valve style and

configuration carefully matched to the specific properties of the fluid being

dispensed.

Difficult Fluids Such as Medical-grade Cyanoacrylate

Wetted internal parts, as well as any fittings and tubing that come in contact with

the fluid, should always be carefully chosen for compatibility with the fluid being

dispensed.

When working with the cyanoacrylates used in catheters and stents, for example,

diaphragm valves with wetted parts made of inert, Ultra High Molecular Weight

(UHMW) polymer are a good choice because they will not react with the fluid. Nylon

or metal fluid fittings, however, should never be used with cyanoacrylates because

they absorb moisture and will promote premature curing. Use polyethylene or

polypropylene fittings instead. Chemically inert, polyethylene-lined or PTFE FEP

tubing is a good choice for fluid feed lines.

Thin to Medium Fluids

Thin fluids like solvents and watery adhesives have much different requirements,

especially when very small deposits are needed. For these applications, needle

valves are often recommended because shutoff occurs close to the valve outlet or

dispense tip. This is an important design feature because it minimizes dead volume

that can cause dripping or oozing.

When applying fluids in critical applications such as needle bonding, there is even a

needle valve that “seats” the needle in the dispensing tip instead of the valve body.

By virtually eliminating dead volume, this design makes it possible to produce even

smaller and more consistent microdeposits.

Thick Fluids

Thick materials like sealants or the RTV silicones used to bond pacemaker

assemblies, for example, pose very different challenges than thinner fluids like

adhesives or solvents.

When using thick fluids, a high-pressure valve with a balanced spool design will

provide good control. Also look for a snuffback feature – it will prevent drooling and

tailing, and help reduce the rework and cleanup often associated with these more

challenging assembly materials.

Best results will be obtained when the

valve design is matched to the properties

of the fluid being dispensed.

Diaphragm valves

with inert wetted

parts are a good

choice when working

with reactive fluids.

Needle valves minimize dead

volume when making very small

shots of thin fluids.

Needle Seat

Piston valves have snuffback to

keep thick fluids from drooling.