“Should we install ventilation for our ultraviolet (UV) light-curing process?”

Well it depends… We’ve addressed this question from an overall chemical-usage perspective since our answer looks at the “bigger picture”, not just the UV light-curing process.

When determining the ventilation requirements for a specific chemical or process, you must consider the following:

1. The size of the room. (In a larger room, you may be able to incorporate normal room ventilation to dilute chemical fumes or vapors below permissible exposure limits)
2. The volume of chemical being used. (Larger volumes of chemicals may pose greater health and safety concerns)
3. The physical and health hazards of the specific chemical. (More hazardous chemicals such as corrosives, solvents or flammable liquids may require venting. Always consult the material safety data sheet for information and special instructions)
4. The chemical state, vapor pressure, and vapor density (i.e. gas, liquid or solid) will help determine whether ventilation is needed, will work, and where to install it if it is needed.
5. Monitoring chemical levels in the workplace. (If levels are below permissible exposure limits, there may be no need to vent or exhaust) Additionally, if a ventilation system is put into place you must re-evaluate exposure levels to chemical fumes or vapors within the work area. This will determine if additional protection is required.
6. Atomization of the airborne chemical. (It is always recommended to vent or exhaust a chemical if you are spraying it)
7. How often the chemical is being used? (When combined with other factors, this could help drive a company’s decision whether to vent or not)
8. Cost. (this is always an important factor)

In the case of a UV light-curing process the answer also depends on the amount of heat generated by the UV light-curing system and the impact it has on the performance of the HVAC system in the area.

Ultimately, the decision to install a ventilation system is up to the user of the chemical after a thorough hazard/risk analysis (including workplace monitoring) is completed.

Curing Equipment, Safety Curing Equipment, Safety, Ventilation

Another question that came through recently:

“I’m looking for assistance bonding a Teflon^® wire jacket to a PEEK housing. Do you have an adhesive recommendation?”

Response:

Teflon^® or polytetrafluoroethylene (PTFE) is a low-surface energy plastic used in a variety of different industries from non-stick cookware to wire jacketing. Its accidental development led to the unique characteristics we have come to associate with Teflon, such as its use as a low-friction coating or non-stick surface. Because of these unique properties, Teflon presents many challenges to adhesive manufacturers whose customers wish to bond to it.

PEEK or PolyEtherEtherKetone is a high-performance polymer ideal for high heat-resistant applications where dimensional stability is needed. Its excellent chemical resistance makes it an ideal choice for many automotive, medical, and food processing applications. PEEK also presents many adhesive-bonding challenges.

While the question asked seems pretty straightforward, it is far from it. Before any adhesive manufacturer can answer a question like this, additional information is needed to identify a solution.

• The adhesive manufacturer needs to know what industry or market the finished part will be used in. For example, if it will be used in the medical industry, the customer may require a USP Class VI or ISO 10993 approved adhesive.
• Information on how the adhesive will be qualified, such as any temperature, chemical, or strength testing, will help an adhesive manufacturer narrow down their potential list of suitable products.
• Also, understanding the environment in which the final product will operate will provide additional information needed for the adhesive manufacturer to make a qualified adhesive recommendation.

While both substrates are difficult to bond, Teflon is considered to be the more challenging of the two. In this question, bonding the Teflon wire to PEEK may not be feasible. It may make more sense to encapsulate over the Teflon wire to the PEEK using a UV light-curable adhesive instead of bonding the two substrates together. In this case, you would bond to the PEEK by encapsulating the Teflon jacketed wire in place. Provided there are minimal external forces or stresses on the wire, this solution could pass a manufacturer’s qualification testing. In many cases, adhesion to PEEK can be improved by surface treating (i.e. corona, plasma, etc) the plastic before bonding. This will improve the overall performance of the adhesive bond and the quality of the finished assembly.

Any recommendation made by an adhesive manufacturer should be treated as such. The adhesive company will provide a manufacturer with their best candidate for the application based on the information provided to them during discussions with the company’s technical staff. Every company is responsible for determining the success of the adhesive recommendation by testing the performance of the assembly to see if it meets their established test criteria.

Adhesives, Medical PEEK, Teflon

“We are running two DYMAX Fusion UV conveyors to package electronics, but have found when our barcode scanners are powered on channels 6 and 11 (in the 2400 to 2500 MHZ radio spectrum), they are absolutely unusable while the conveyors are turned on. We seem to have a severe conflict. Any suggestions on how to fix this problem?”

Fusion UV lamps generate microwave radiation to energize a UV-emitting bulb. This energy is generated by magnetrons which operate at a fundamental frequency of 2.45Ghz. Wireless communication equipment that operates at the same frequency will likely not be able to handle the interference.

Fusion equipment is classified as non-consumer industrial, scientific, and medical (ISM) equipment, as defined in Federal Communications Commission (FCC) rules and regulations, Volume 47, Part 18, and the International Telecommunications Union (ITU). Fusion also complies with EN 55011 (CISPR-11, Group 2, Class A).

The FCC and ITU give ISM equipment legal priority over all other RF devices in this band.

Wireless devices operating in the ISM band are required to be able to accept RF interference from ISM equipment. If your wireless system is having problems working in the same environment as Fusion equipment, then it is operating at the same frequency but is unable to accept the interference as FCC regulations require.

Some of our customers have had success by repositioning transmitters, antennas, and access points within the facility by using directional antennas and by frequency hopping. The only foolproof way to solve the problem is to change the frequency of the wireless system to a frequency outside of the ISM band, 900Mhz or 5.8Mhz.

If you have not done so already we recommend that you contact your wireless equipment provider to see if they can offer you a solution.

If they are unable or unwilling to help, you can try the following:

Per the  example below, you can try to ‘shield‘ the lamps to reduce the amount of RF emitted into the work environment. You can do this by placing metal mesh screen (1/4″ maximum opening) around the lamp units, by sealing the seams around the lamps and light shield with a metal tape (aluminum tape works well). You might also consider wrapping the cables in metal tape since they radiate some RF as well (you only need to go down a foot or so, its mainly around the connectors).

Image provided by Fusion Systems

You could also install a ground strap from the lamp housing to earth ground using 1″ tinned-copper braided strap.

Should you decide to pursue this approach you need to make certain that the equipment is accessible for servicing and none of the airflows are restricted or otherwise compromised, which could lead to overheating and premature failure of some components.

Curing Equipment Conveyors, Curing Equipment, Radio Interference

Cold-bonding aerobic structural adhesives, those that cure “on demand” without heat, allow manufacturers to assemble parts when they want to without being limited by two-component mixing, additional heating and cool downtimes or oxygen presence within the bond area. Cold-bonding aerobic adhesives provide companies with the ability to bond dissimilar substrates within the production line without having to worry about long fixture times. Because the adhesives experience rapid bond strength development, the parts can continue through the production line without increasing work in process (WIP) times. This means companies who switch to cold-bonding adhesives will improve production efficiencies within their process while experiencing decreased energy costs. All of these are extremely important to companies in today’s current economic conditions. Companies need to explore different methods to become more efficient without sacrificing quality. Cold-bonding aerobic adhesives are one method to help companies.

It reminds me of a story of a company who was using an induction heat-curing epoxy to bond magnets into a cold-rolled-steel motor housing. Not only were they experiencing a number of in-line quality issues but the cool down time to handle the parts added significant WIP and expense to their process. By switching to an aerobic structural adhesive they were able to improve their quality and eliminate any non-valued added steps in their process. This allowed the company to produce a quality assembly quickly while improving their profits.

These adhesives cannot, however, be used in all applications and are only recommended when alternative bonding methods such as ultraviolet light-curing adhesives cannot be used. Aerobic adhesives have been successfully used in DC and brushless DC motor, speaker hardware, and opaque metal and glass bonding applications, in some cases exceeding the strength of one of the substrates.

How do they cure? Aerobic structural adhesives are two-component but in a non-traditional manner. Cold bonding technology incorporates a liquid activator and (usually) a gelled adhesive. As shown in the picture to the left, adhesive is applied to parts of a motor, in this case the magnets. Unlike a two-part epoxy where the components are statically mixed together, the activator for the aerobic adhesive is applied to the opposite part, in this case to the motor housing. Once the parts are ready to assemble, the magnets are pressed into the motor housing. The adhesive spreads through the activator, filling any gaps that exist between mating parts. As the adhesive spreads through the bond area and activator, this mixing action starts the curing within seconds and eventually finishes it. Again, there is no need to batch or rack curing parts since the buildup of strength is immediate and ongoing, allowing manufacturers to keep the assembly within the production flow.

Aerobic adhesives do not work in all applications, but should be selected as an alternative to cyanoacrylates, second-generation acrylics, induction heat-curing and two-part epoxies, and anaerobic adhesives. Each application should be reviewed with the technical staff of the manufacturers’ products that you are considering using. Changing to a new adhesive should only be considered after you have thoroughly tested the performance of the assembly to see if it meets your established test criteria.

Structural Adhesives, Cold Bonding, Dissimilar Substrates, Structural

REACH, BPA, DEHP, WEEE??? This is not your mother’s alphabet soup but acronyms for new environmental compliance directives, regulations, and initiatives…

As the world shrinks and companies continue to span many continents, we are seeing an increase in global environmental and safety regulations.  Many of these are being initiated in Europe and are spreading throughout Asia and within our own country.  Directives like REACH, WEEE, RoHS, and GHS are driving many companies crazy as they try to understand how the directives affect them.  Initiatives to identify and eliminate DEHP and BPA use in plastics and adhesives are also plaguing many manufacturers.  Very few international companies are immune from these new directives and initiatives.

It’s important to understand each one and how it affects your specific business before investing resources.  In today’s economy companies must invest their resources wisely in order to stay competitive.  It is important to understand the impact of these new regulations and initiatives both financially and from the safety and compliance perspective before moving forward. 

What are they?

REACH, a new European Community Regulation on chemicals and their safe use, entered into law on June 1^st 2007.  The legislation addresses the Registration, Evaluation, Authorization and restriction of Chemical substances.  The main objective of REACH is to improve the protection of human health and the environment from the risks that can be posed by chemicals used in an industry.

REACH makes industries responsible for assessing and managing the risks posed by these chemicals and provides the appropriate safety information to their users.  The criterion is based on volume (equal or greater than 1 metric tonne) imported into the European Union (EU) or if it is a Substance of Very High Concern (SVHC).  Registration of the substances occurs in phases based on the previously mentioned criteria, with the last occurring in 2018.  Learn more. 

WEEE or Waste Electrical and Electronic Equipment is another directive (Directives 2002/95/EC & 2002/96/EC) from the EU which restricts the use of hazardous substances (see RoHS) in electrical and electronic equipment while promoting the collection and recycling thereof.  The recycling program is aimed at re-using electronic waste and encourages consumers to return outdated, broken electronic equipment to the manufacturers at no cost to the consumers.  This eliminates the used electrical and electronic equipment from ever reaching a landfill where it would contaminate the environment with harmful substances that could potentially leech out.  WEEE goes hand-in-hand with RoHS.  Learn more.

RoHS or the Restriction of Hazardous Substances (directive 2002/95/EC) works closely with WEEE and is designed to shift manufacturers away from restricted chemicals to safer alternatives.  The EU identified the following substances under RoHS as hazardous with a significant impact to the environment.  They are: 

• Cadmium (Cd)
• Lead (Pb)
• Hexavalent Chromium (CrVI)
• Mercury (Hg)
• Polybrominated biphenyls (PBB)
• Polybrominated diphenyl ether (PBDE )

Additionally, the EU restricted three other flame retardants under 2003/11/EC for their negative impact on human health and the environment.

• Pentabromodiphenyl ether (PentaBDE)
• Octabromodiphenyl ether (OctaBDE)
• Decabromodiphenyl ether (DecaBDE)

Please click here for more information. 

GHS or Globally Harmonized System of classifying and labeling of chemicals is a regulation that was created in collaboration with the members of the United Nations (UN). Essentially, this regulation looks at unifying and standardizing all classification and labeling of chemicals so they are globally harmonized.  This means whether you are in Russia, France, Mexico, or the United States the safety information would be communicated in an identical manner through pictograms, hazard warnings, signal words, etc.  Read more from the OSHA website. Each specific country’s adoption of this new standard will vary.  Click here to learn more about your specific country’s adoption schedule for GHS.

DEHP and other phthalates

Di(2-ethylhexyl)phthalate (DEHP) is a plasticizer added to polyvinyl chloride (PVC) to make the normally rigid plastic more flexible.  Many companies, especially those in the medical device industry, are requiring suppliers to inform them of DEHP or other phthalate use.  The FDA issued a health warning¹ advising the public that DEHP could leech out of PVC and pose a health risk in certain high risk groups.  Specifically, there are concerns pertaining to the effects on the development of the male reproductive system.  More information is available from the FDA website.   

BPA

Bisphenol A² is a key ingredient in the manufacturing of polycarbonate and a constituent within many epoxies.  “In recent years, a hypothesis has been advanced claiming that exposure to extremely low doses of certain substances could cause adverse health effects in humans, including disruption of normal hormonal functions.”² There have been many conflicting studies completed showing that in some cases there is concern to human health but in other studies demonstrating no harmful effects.  Based on some initial tests through the National Toxicology Program (NTP) it appears as though there is “some concern” especially in small children and infants.  To alleviate some of the discrepancies in testing, NTP is requesting additional information from the scientific community pertaining to the health effects of BPA.³  It may be years before we really know whether there is truly a concern with BPA.  It will probably be too late for industry however, who regardless of the outcomes, will have made the switch to BPA alternatives because of these initial concerns.   More information on BPA can be found here.

Is there any good from these regulations and initiatives?

While many of these regulations and initiatives may be seen as cumbersome and confusing, some of them really are.  They make sense when you look at the overall picture and what is trying to be accomplished.  Many of the regulations are needed to reduce the impact and bioaccumulation of harmful chemicals in the environment, while minimizing or eliminating any risk to the safety and health of the greater population.

DYMAX ECO Benefits Everyone

DYMAX understands that safe ecologically friendly products benefit our customers, the environment, and us. We have created materials with attributes that lower products costs, life-cycle costs, and ecological impact. Learn more…DYMAX Eco underlines the DYMAX commitment to the environment.

¹ Retrieved from the FDA website http://www.fda.gov/MedicalDevices/Safety/AlertsandNotices/PublicHealthNotifications/ucm062182.htm

² Retrieved from the website http://www.bisphenol-a.org/

³ Retrieved from the website
http://www.ehponline.org/docs/2009/117-3/EHP117pa96PDF.PDF 

Safety BPA, DEHP, GHS, REACH, RoHS, Safety, WEEE