My HPC Laser cutter has broken down. It needs servicing, but is it safe?
At Kent Lasers we take safety very seriously. It is unacceptable to put users at unnecessary risk when using a tool ,such as a laser cutter which have become commonplace in schools colleges and the workplace. Below we discuss the very common safety shortcomings of the HPC brand of Laserscript laser cutting machines which have been found whilst servicing equipment for various clients. (All images and videos taken from actual service calls) HPC are manufactured in Jinan, China by King Rabbit, a company that produce some of the cheapest, most outdated and lowest quality equipment we have ever seen.
The Machinery Directive; An overview:
The Machinery Directive (2006/42/EC) is a piece of legislation covering industrial devices and products which are sold in the UK and the European Union. You may be forgiven for thinking this document is just another piece of "red tape" legislation, however it states some very important safety rules for industrial equipment, specifically to safeguard consumers from dangerous products and equipment. In principle this directive states:
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Equipment must be designed as such that operation and servicing does not put users at risk.
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Guards and covers must prevent access to hazardous areas, and give a stop command if removed, preventing dangerous machine functions, whilst users are in a "danger zone".
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Manufacturers must design equipment to be inherently safe, including reasonable foresight for user error and abuse.
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Equipment fitted with laser devices must be correctly classified. No exposure to direct or reflected radiation should be possible.
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Equipment powered by electricity should not pose any electrical hazard.
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A stop device should be fitted, which is within reach of the user, and stops all dangerous functions.
Equipment should therefore be designed in such a way as to incorporate all of the features listed above. This is crucial with the optical hazards present with laser devices, as the eyes and skin are very sensitive to exposure from CO2 laser light even at low intensity for very short durations.
Common issues with various HPC Laserscript laser cutters.
HPC Laser will not cut, or only cuts in certain areas of the bed:
The laser tube, usually installed in the rear of your laser cutter, produces an intense beam of coherent light in the near-infrared spectrum (around 10.6um). This light (which is invisible to the eyes), is reflected via a series of mirrors and through a focussing lens towards the workpiece, where cutting takes place. It is absolutely vital, for both safety, reliability and consistency of cut, that the laser tube, and mirrors are held firm, usually being bolted down to a solid chassis to prevent these vital components from moving and thus becoming mis-aligned. Consider that the mirror adjustment, and correct calibration of your laser cutter is vital for cutting to take place. Minor misalignments of the beam can be the difference between the laser cutter being able to process materials, or cuts failing. From a safety perspective, if these components are not secured, the beam can deviate by a considerable, unknow and often dangerous margin. Safety Verdict: FAIL
When checking cuts, I often look through the front panel, is this OK?........ NO!
As the Machinery Directive states, exposure to the laser must not be possible when the machine is in use. A stop command MUST be sent when guards are not present which halts dangerous functions/processes. The image opposite, of an HPC "Pro" laser cutter demonstrates the absence of any interlocks on the access panels/guards. This allows for direct viewing into the machines cutting area. Any scattered, or reflected laser light has the potential to cause permanent damage to the eyes, burns to the skin and combustion of materials. It should therefore not be possible to operate the machinery with guards and panels removed, as this presents a serious exposure risk to the user. Safety Verdict: FAIL
When I open the lid on my HPC Laserscript cutter the laser stops, so its safe right?
A safety stop on the main lid of your HPC laser cutter is an absolutely essential device, which prevents the laser from firing when the machine is open. This is even more important when the equipment is used in schools, where students have access. However we have found (on almost every HPC Laserscript machine we have tested) that these interlocks do not function adequately, allowing the lid to be opened by a considerable margin before the stop signal is achieved. This not only makes possible the direct viewing of the laser beam, but allows for hands and arms to be put inside the machine whilst running (for instance if materials move, or adjustments need to be made during a job/design) Our engineer was able to insert hands and arms into the area of the machine(s) on the 3 examples below allowing direct contact and viewing of the beam path. Safety Verdict: FAIL
When using my HPC laser cutter I always keep the lid closed when in use....
This is good practise, and very much recommended, however these machines are so poorly built many of the panels which make up external portions of the machine are not properly manufactured, and often very loose fitting. Common areas of concern are the left-hand side of the lid (directly above the beam path), rear of the machine where the lid meets the tube compartment, various louvers and ventilation holes, which all allow direct viewing of the cutting area.
These areas of the machine should feature labyrinth seals, whereby airflow is allowed, but direct viewing is blocked by a series of inner panels or baffles. Direct viewing of the cutting area should not be possible, furthermore any materials which fall into these gaps can instantly combust. Safety verdict: FAIL
I've heard that glass laser tubes use high voltage, is this dangerous?
DC Driven "glass tube" CO2 lasers do not pose any electrical safety hazards if implemented correctly. This means their high-tension connectors and cables (similar to the ignition leads in your car) are required to be made from durable materials, have the correct insulating properties and are solidly terminated/connected to their respective components. Furthermore any metal casing that houses these devices must be grounded (protective earth) to ensure that should an electrical fault occur, all hazardous currents are drawn safely to earth, and away from the user.
Unfortunately we have found that on various HPC Laserscript machines panels and metal parts which are in reach of the user are not grounded. This poses a serious safety hazard as if an internal electrical fault were to occur, the user may not be fully protected. Safety Verdict: FAIL
Furthermore, we have frequently found faulty wiring on these machines. This involves the high-tension cables (which carry many thousands of volts) not being adequately terminated to the laser tube terminals. We have found these wires, glued, taped and even loosely wrapped - not good practise when dealing with such high voltages and when various parts of the machine have exposed metal (and non grounded) parts.
Due to the above, we are very reluctant to provide service for any laser cutting machines that have the above quality issues and faults. It may be possible to provide re-work of basic faults, however, we suggest clients fill out our contact form to discuss how we can ensure your laser cutting equipment has genuine safety conformity and is safe for commercial and educational use. (Any machine with the above issues would fail a safety inspection).
If you are looking for a safe and reliable laser cutting solution for your classroom, or business we offer our own range of systems, designed and manufactured in the UK, with the latest features and technologies. Our range can be found here. At the very least, please be aware of the above issues before buying a Chinese laser cutter machine from an importer or dealer.