Mazak 3D - Precitec Type Cutting Head Troubleshooting
This article will go over the proper procedure to test the Precitec Type cutting head that is used on older Mazak 3D lasers such as the Space Gear and Fabri Gear. Make sure to check out our video for a visual aid and our catalog for an individual product listing. First, we will go over how to identify a cutting head as the Precitec Type version. Then, we will demonstrate how to check the resistance and continuity at different test points on the unit using an ohm meter.
Identifying the Precitec Type Unit
A unit is identifiable as a Precitec Type cutting head if it has the blue nut located next to the sensor cable connector. This feature is not part of the Mazak Type cutting head. The blue nut is actually a plug that is sealing a port for cooling air. When these models first came into service, there was an airline connected to them. Other brands of lasers that use this same cutting head may be still using the port for cooling air. Mazak later decided that there was too much risk of interference from this air with the oxygen or nitrogen assist gas that is used during laser cutting, leading to them creating the Mazak Type cutting head.
How to Test the Precitec Type Cutting Head
Let’s go through the different steps required to complete the test.
Using your multimeter or ohmmeter
You’ll need an ohm meter, or as we have in our video, a multimeter set to “ohms”. A digital or analog meter could also be used. Many multimeters or ohmmeters will automatically adjust the scale or range of measurement, but be aware that some require you to set the scale. This is a range of measurement that will most closely match the resistance you are measuring. Often the scale, or range of measurement, is marked in some way to identify ohms in the range of tens, hundreds, thousands, ten thousands, one hundred thousands, and so on. It might be marked as 200, 2000, 20k, 200k, 2M. If you have an ohm meter that requires you to set the scale, you need to set it to the lowest scale higher than the resistance you are measuring. In this test, the value we are looking for is 100k ohms. If you do not have an auto-scaling meter, you’ll need to be set at the scale of 200k. In our video, we have an auto-scaling meter so we just set the dial to ohms, marked by the symbol “Ω”.
Begin the testing process
The most common problem to have with this cutting head is that the resistance between the inner cone and outer cone is open. This occurs if the cutting head is dropped, crashed, or if it experiences a high temperature spike; any of these situations can damage the internal circuit of the cutting head.
Test the resistance between the inner and outer cones
The first step is to measure the resistance between the inner and outer cones. Set the cutting head on a table that does not conduct electricity, such as wood or plastic. A metal table will interfere with the test and lead to inaccurate results. Set your multimeter to ohms, or your ohm-meter to the scale of 200k. Touch one lead of the meter to the inner cone and the other lead to the outer cone, as shown at the beginning of the video. There is no polarity to consider when measuring resistance, so the black or red lead can touch either the inner or the outer cone. The measured resistance should be about 100k ohms. The “k” is a range abbreviation meaning this measurement is 100,000 ohms. In our example on the video, we are seeing 99k ohms. This resistance measurement should be within around 1% accuracy, meaning the acceptable range is between 99k and 101k ohms. If the resistance measure is outside of this range, then the cutting head unit has a problem. Usually, the problem here is the resistance will be infinite, or “open”, meaning that there is no resistance because the circuit inside the unit is damaged.
Test the continuity from the connector pin to the cones.
The next test to perform is the resistance measurement from the inner pin on the connector to the outer cone. This is demonstrated at 30 seconds on the video. The purpose of this test is to make sure the connector has a proper internal connection. Carefully hold one of the leads on the pin of the connector while touching the outer cone with the other lead. Again, for this resistance measurement, there is no polarity so the black or red lead can be used on either side. The resistance measured from the pin of the connector to the outer cone should be the same value as measured from the inner to outer cone, in our example the value measured is 99.6k ohms.
The next test to complete is to measure from the connector pin to the inner cone. This measurement should be less than 1 ohm, indicating that there is a direct short from the pin of the connector to the inner cone. If this resistance is over 1 ohm, or if there is no resistance showing there is an open circuit, this indicates there is a bad connection inside the cutting head.
Conclusion
After testing the resistance between the inner and outer cones, the resistance from the pin to the outer cone, and the resistance from the pin to the inner cone, you will be able to determine if there is a problem with your Precitec Type cutting head. If your unit tested properly and you are still experiencing a problem with your system such as a frequent “Auto Gap Alarm”, it could be that you need to calibrate the “Gap”, also called the “Pofiler” or the “Tracer”. Follow the link below to view our video on gap calibration for the Precitec Type Profiler:
Gap Calibration for Precitec Type Profiler Video
If your Precitec Type cutting head test indicates that there is a problem and the unit is damaged, you can send it in to MG Laser as a trade-in for a refurbished unit. We will fix your cutting head and put it back into our inventory for the next trade-in. We typically have refurbished cutting heads in stock and ready to ship, however, you can check with us regarding inventory by emailing us at parts@mglaser.com. Find the refurbished Precitec Type Cutting head product listing on our website here. You can also find a new Precitec Type Cutting head here.
We recommend that you keep two cutting heads on hand at all times. This way, one can still be used while you are waiting for the second one to be repaired and returned, minimizing downtime.
Next Steps
If your system still has an “Auto Gap Alarm” that will not clear, and your Precitec cutting head has passed the above procedure, the problem could be in the sensor cable or the Preamp. The sensor cable connects the cutting head to the preamp.
The sensor cable can be found on our website using the following link:
Sensor Cable for Precitec Cutting Head
The Precitec Preamp can be found on our website using the following link:
The final item in the circuit that can cause a problem is the main non-contact amplifier. It could require calibration or it could be damaged. If you made it this far and need to test your main amplifier, please give our service department a call at 312-953-2215.
Check our service blog post for more information regarding our repair and other services for Mazak lasers.