trying to keep my eye on the ball and ignore the drunken hecklers in the crowd.
Still can't hit that "buy" button, though,...
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Conventional turning operations are a standard of round part production throughout the world and especially common in automotive components. As the cutting tool removes material it creates a “chip”. In theory the cutting tool creates a chip that is rather short and they fall to the bottom of the machining center to be conveyed away. In practice these chips can become very long and wrap themselves around tool holders and fixtures; they can mar the surface of the part, and be extremely difficult and hazardous to handle and convey to a hopper not to mention the need for coolant to try to help break the chip. All these issues hamper machining operations in terms of automated load/unload, automated gauging, tool insert life, and yield. The use of lasers to control the chips is a novel new patented application with incredible potential.
Machining systems have to use tool inserts with “chip breaker” geometry to try and break the chips, however, they can only work at certain surface speeds and this is never a constant in machining processes. They also impart a lot of extra force during turning that reduces tolerances and requires more passes. Mild steels like 1008 and 1010 are so ductile that breaking a chip is very difficult. The use of coolant to try and help with chip breaking results in much higher costs, skin reactions, and very high potential health hazards.
Americhip LACC has a patented process to use a laser to create a scribe on parts to eliminate these chip problems. They call it Laser Assisted Chip Control.
Using a laser to put a scribe into the raw part that extends down to within a few hundred microns creates an interrupted cut during turning that separates the chips for total chip control. The distance between laser scribes on the part can be adjusted to define the actual chip size and the depth of the scribe is adjusted to match the amount of material removal needed for the final part dimensions. Scribing the part for chip control is a simple first step before machining; however, it does much more. Removing the chip control problem allows for dry machining with lower-cost, tool inserts and a predictable tool life. It also reduces the number of machining passes needed, slashing costs. Also, since the chips are controlled and no longer wrapping themselves around the tools, parts, and fixtures, then automated machine loading and unloading, automatic gauging, and automatic tool changing is possible without fouling.
The laser scribe is easy to automate; there is no contact or tool wear. A coaxial gas nozzle with a capacitive height sensing using the Robotic Cutting Head with air assist blows the debris out of the scribe line creating the scribe. Increasing laser power or slowing laser speed will create a deeper scribe. Changing the laser output waveform can also be used to adjust scribe depth. The laser can employ a Time-Share multiplexer to allow sequential scribing at two separate stations or an Energy-Share for simultaneous scribing.
Pulsed YAG lasers and Super Modulated CW YAGs are the best choice since they produce the pulse energy and peak power for efficient scribing with minimal heat input. For deep scribes a high peak power pulsed YAG like the JK704 is used for. For most applications, a high power beam quality unit with a small fibre optic produces a very good scribe with the most economy. The laser model is chosen based on the scribe depth required, the cycle time constraints, and the economies required. Coaxial air or oxygen is used to aid in the scribing process and keep the optics clean. |
