There are only two sounds that come from a manufacturer’s shop floor: the sound of making money; or the sound of spending money. And nothing drains capital from a manufacturer faster than the deafening sound of silence. In this interview, SigmaTEK’s Kevin Keane explains the cause, impact, and solution to laser cutting head crashes.
What is the main reason for laser cutting machine crashes?
Keane: Damage to the laser head generally occurs as a result of collision with parts or island scrap on the cutting table. This is most often caused by cut parts, or loose material between parts, that have shifted during the run and stick up above the material surface. When the cutting sequence takes the head back into the vicinity of a previously cut part there is always the chance of a collision with a protruding part.
How big of a problem is this?
Keane: Typically laser head replacement can run between $10,000 and $30,000. Likewise machine-time and man-hours lost recalibrating or replacing damaged cutting heads are significant. If you consider that the machines are very expensive and that the throughput is higher than ever, it follows that every minute of machine time is worth more to your business. Every minute that the machine is not cutting correctly or has stopped costs you more money than ever before.
In a typical day a fabricator has a limited number of hours to make a profit – no profit is realized until all costs are covered. This imaginary line when a company begins making money does not come at the beginning of the day. In an eight-hour shift the transition won’t likely occur until the final couple of hours. So naturally any downtime shortens the work day shrinking the window on profitability.
OK What’s the solution?
Keane: Today sophisticated software can safely squeeze every bit of speed from cutting machines while anticipating and avoiding issues associated with crashes. Here are a couple of things to look for in a manufacturing software program:
Number one – Intelligent Sequencing of processing that protects the machine as well as maintaining part quality and being time efficient. This involves processing the parts as well as the features of each part in a sensible order.
Secondly – Avoidance of previously processed areas that pose a threat. The software will need to have the smarts to recognize areas of danger. Some examples are tipped up parts, floating scrap and the like.
Won’t this negatively affect cutting speed?
Keane: When one weighs the risk of a stoppage, it is often faster to go around a part than to cross over. Today’s lasers can position at speeds in excess of 3000 in/min or 50 in/sec. Large parts are more likely to lay flat posing minimal risk. Conversely, parts that have a width less than the gap between 3 table slats are the most dangerous. These parts are probably less than 12″ in either X or Y for most machines.
For example, a 12″x12″ part will be 16.97 on the diagonal. To cross this part fully might take up to 0.339 seconds. On the other hand, to go around this part and avoid it entirely will be 24″ of travel or 0.48 seconds. So in the literal blink of an eye, 0.15 seconds of travel completely eliminates the risk of a crash. So while it might be slower — it will probably be faster.
Any final thoughts or recommendations?
Keane: Productivity is more than just simple speed. The road to profitability begins with keeping machinery running at full capacity. Fortunately SigmaNEST has kept pace with cutting machine advancements to maximize cutting productivity while leveraging the physical cutting capabilities of the equipment to its fullest.
Kevin Keane is Product Manager for SigmaTEK Systems responsible for tool path generation and post processing. Learn more at www.sigmanest.com.