Newsletter 221: Marking Steel Connectors, Kiss-Cutting Keypad Templates, Stripping Fluoropolymer Wire Insulation

SYNRAD, INC. - http://www.synrad.com
Thursday, September 17, 2009
Issue 221

Applications at a glance


Marking Stainless Steel Connectors	Kiss-Cutting Keypad Templates	Stripping Fluoropolymer Wire Insulation

SYNRAD's sealed CO2 lasers are used in a variety of industrial processes including cutting, welding, drilling, and marking. This news brief showcases some of the interesting materials and products that are processed daily by Synrad's line of CO2 lasers and marking heads.

Marking Stainless Steel Connectors

Manufacturers specify stainless steel for a variety of consumer and industrial products because of its corrosion resistance, durability, and aesthetic appeal. Stainless steel performs well in both high- and low-temperature environments, and the ease with which stainless is cleaned and sanitized makes it the ideal choice in the health care, pharmaceutical, and food processing industries.

The fast rise/fall times of Synrad's firestar t-series technology makes it an excellent choice for marking stainless steels.With rise/fall times less than 75 microseconds
(< 0.000075 seconds), our t-series lasers provide a greater depth of modulation for a given marking frequency. This means that a larger percentage of peak energy is applied during each 'laser on' pulse.

Laser Marked Steel Connector

A nicely contrasting 10 character code was laser marked on 316 stainless steel with 60 watts of power in a cycle time of only 0.22 seconds.

To mark this right-angle electrical connector that is stamped from 316 stainless steel, we set up an FH Series marking head with an 80 mm lens to achieve a 116-micron (0.005") spot over a 33 mm by 41 mm (1.3" x 1.6") mark field. In WinMark Pro, we created two text objects and typed a fixed part number for the first part of the code. The second half of the date is a Julian date code (DDDY format) that is set to increment automatically based on the marking computer's system clock. To format the text string, we chose a stroke font (Simple), set a Text Height of 2.3 mm (0.09"), and added 0.25 mm (0.01") of Extra Character Spacing. At a Power percentage corresponding to 60 watts and a mark Velocity of 165 millimeters per second (6.5 inches/sec), we marked this 10-character text string in a cycle time of 0.22 seconds.

Kiss-Cutting Keypad Templates Kiss cutting - a process where the laser cuts through a self-adhesive upper layer without cutting through the lower backing material or paper liner - is a common CO2 laser application made possible by the ability to precisely control laser energy. In galvanometer-steered (optical scanner) applications, laser control is provided by our FH Series marking heads, which generate a 20-kHz PWM frequency to obtain the highest mark quality. Additionally, FH Series marking heads provide position and resolution accuracy measuring out four decimal places to several ten-thousandths of an inch for accurate beam placement mark after mark. The requirement for this project was to precisely kiss-cut keypad templates from sheets of laminated plastic film. Exacting power control was especially important in this application since the template design had to be completely cut out of 0.08 mm (0.003") thick plastic without damaging the 0.04 mm (0.0015") thick backing film.			These keypad templates were kiss-cut from sheets of 0.003" thick laminated plastic film using 60 watts of power at a speed of 50 inches per second in a cycle time of 0.73 seconds.
We accomplished the task using a Synrad sealed CO2 laser and FH Series marking head driven by our WinMark Pro laser marking software. A 125 mm focusing lens was installed in the marking head to create a 180-micron (0.007") spot size with a 3 mm (0.118") depth of focus. The keypad template, created as a .PLT (HP Graphics Language) file, was imported directly into WinMark Pro at full-size, one-to-one scale. To kiss-cut the keypad design, we assigned the following mark properties to the imported graphic object: Power, duty cycle percentage, was set to correspond to a laser output of 60 watts, Velocity was set to 1270 millimeters per second (50 inches/second), and Resolution was set to a value of 300. At these settings, the entire design was cleanly kiss-cut, without damaging the backing material, in a cycle time of 0.73 seconds.

Stripping Fluoropolymer Wire Insulation

Fluoropolymers are thermoplastic polymers where some or all of the hydrogen has been replaced by fluorine. These materials (TFE, PFA, PVDF, etc.) are resistant to high temperatures (including fire), chemicals, weathering, and abrasion. They also exhibit low coefficients of friction, high dielectric strength, and are chemically inert. Taken together, these properties define the ideal material for insulating electrical wire.

The fluoropolymer connection to CO2 lasers is twofold: First, fluoropolymers are easily vaporized by the CO2 beam; and two, copper and aluminum wire are reflective at the 10.6 micron wavelength. Because the wire is not nicked or damaged by the laser beam, wire stripping remains an excellent CO2 application.

We cut the fluoropolymer insulation from this electrical wire without damaging the wire. The heavier 10 AWG coating, measuring 0.0135" thick, was cut using 200 W at a rate of 1800 IPM.

This article highlights a proof-of-concept test for stripping 10 AWG and 26 AWG fluoropolymer-coated wire. The demonstration setup consisted of a Firestar f201 (200 W) laser, an XY table for beam delivery, a 63.5 mm (2.5") focusing optic and clean, dry air assist at 0.34 bar (5 PSI). Our choice of optic provides a 100-micron (0.004") spot with a 1.8 mm (0.07") depth of focus.

The 26 AWG wire, the smaller wire in the photo above, has an 0.08 mm (0.003") thick insulation coating that we ablated at a speed of 22.9 meters per minute (900 inches/minute) using 50 watts of power. At the 100 W power level, we achieved a cut velocity of 50.8 meters/minute (2000 inches/minute).

When stripping the 0.34 mm (0.0135") thick fluoropolymer coating from the 10 AWG (larger wire), we cut through the coating at a speed of 22.9 meters per minute (900 inches/minute) using 100 W and cut at a speed of 45.7 meters/minute (1800 inches/minute) using 200 W of power.

In actual production circumstances, an integrated CO2 wire stripping machine would create a complete cut around the wire circumference so that the insulation is easily removed in preparation for termination or soldering. In specialized applications involving ribbon or multi-connector cable, the beam is scanned across the wire to strip selected conductors at predetermined points so that individual conductors are only connected to specific components along the wiring path.

Browse Synrad's Applications Database

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http://www.synrad.com/search_apps/Default.htm

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