Laser welding plastic was highlight of MDM East

I was asked to write a BLOG for Industrial Laser Solutions andcharged headlong into it a couple of months ago without even knowing what aBLOG was or is. So, if we turn to the web, we find the definition: “What's ablog? A blog is a personal diary. A daily pulpit. A collaborative space. Apolitical soapbox. A breaking-news outlet. A collection of links. Your ownprivate thoughts. Memos to the world. Your blog is whatever you want it to be.There are millions of them, in all shapes and sizes, and there are no realrules.” Ok, I can dig those conditions, especially the 'no real rules' part,although my editors might not agree! Anyway, on to the topic of this blog: theMedical Device Manufacturing show …

This is the second (andlast!) year that this conference was held in Philadephia. It was moved from NYCduring construction on the Jacob Javitz Center, and it will return again nextyear to the city where it had been located for many years. Based on thefeedback from vendors and personal observations on the show floor, it seems agood move. The show was comparatively slow both last year and this year,closing at 4 pm presumably because traffic in and around the city is sohorrible. I grew up in PA just north of Philly, and we always heard as kidsthat the roads in PA are the worst in the nation; it seems like some thingsnever change. One thing positive is the location of the convention centerdirectly across the street from the Reading Terminal Market – a place where youcan get anything and everything to eat and is the home of the famous PhillyCheese Steak. Last year, I met more customers at the market than on the showfloor!

Besides the usualmicromachining and marking applications, the thing that really caught myinterest was the plasticwelding. IPGPhotonics has been promoting a 2 micron (1940 nm to be exact)wavelength laser recently. According to Dr. Tony Hoult of IPG, this laser is ofinterest because of its higher absorption than at 1 micron wavelength of manymaterials, such as water and most if not all hydrocarbons. Alternatively, mostsemiconductors absorb less. [Note that Dr. Hoult, a member of the ILSEditorial Board, will be writing an upcoming feature in Industrial LaserSolutions on 2 micron fiber applications.]

Most plastic weldingapplications require a transparent top layer and an absorbing bottom layer inorder to make the weld. If both layers are equally transparent, then sometimesan absorbing adulterant is placed in between to initiate laser welding. Withthe 2 micron laser, it has been shown that even two otherwise ‘transparent’materials can be welded cleanly, quickly and efficiently – the so calledClear-Clear weld. As in all welding applications, the best joints are made whenthe materials are in intimate contact with each other, so fixturing, jigging,and tooling are very important to the success.

A well known player, LPKF fromGermany, unveiled its new PrecisionWeldproduct line at the show. It is specifically designed for finemicrofluidic weld seams with typical weld widths of 100 microns andrepeatability of 10 microns. The tool uses an IPG Thulium fiber laser and hasoptions for part handling and in line inspection of the weld. Usingdifferential pressure clamping, parts can be held in an air-tight grip,assuring 100% contact between the upper and lower plates. By also holding thefocus very close to the weld plane, a perfect weld can be made. This technologyis extremely useful in manufacturing microfluidicdevices, lab-on-a-chip devices, and atomizers. The photo above, courtesyof LPKF, shows an atomizer that dispenses precise amounts of activeingredients.

I am always interested in hearing your thoughtsconcerning laser micromachining, the laser industry, comments onentrepreneurial endeavors, etc. AND … we are always looking for fresh,publishable material. Please feel free to contact me at