Choosing the Right Laser Marking Lens for Deep Hole Applications

When choosing a deep hole laser marking lens, five core parameters-the focal length, depth of field, and beam quality-are key to achieving the desired results.The book begins with practical needs, and analyzes how to select the appropriate lens based on the characteristics of the materials and the precision of the processing, in order to avoid the problems of low efficiency or equipment damage that result from the parameters not matching.

Why is it more important to select the right lens than the right camera?

Many friends spend a lot of money on high-end lasers, but the results are still not ideal. This is probably because the lens is at fault.The parameters of the deep-hole laser marking lens are like those of a camera phone: no matter how high the pixel count, a blurry lens will still produce a blurry image.Today we'll break it down into bite-sized pieces and explain how to avoid the pitfalls of "similar-looking" products.

The first key parameter: the focal length determines the working distance.

A short focal length is suitable for delicate carving.

Lenses with a focal length of 50 mm or less are suitable for precise marking in small spaces, such as the serial numbers on parts inside cell phones.But be careful, the work is so close that the lens can get covered with material.

For deep holes, he uses a telephoto lens.

If the hole is deeper than 100 mm, only a lens with a focal length of 150 mm or greater can be used to ensure that the laser beam does not disperse.Last year a friend of mine who makes oil pumps for cars had a loss when he used a standard lens to mark them. The characters at the bottom of the holes were all blurred together like a QR code.

The second key parameter: Don't compromise on depth of field.

Depth of field is like the focal range of a camera, and it directly affects the consistency of the depth of the marking.When testing, a rough method is to stack the standard blocks in a stair-step arrangement and mark them. If the difference between the top and bottom blocks is greater than 0.1 mm, the lens needs to be replaced.We especially remind our friends in the medical equipment field that cutting costs here is a very risky proposition.

The third key parameter is the quality of the light spot, which depends on its uniformity.

Don't just look at the smallest spot size figures in the sales brochures.The most important thing is whether the energy distribution of the spots is uniform. If you print a grid pattern on thermosensitive paper, and the lines are uneven in thickness, this means that there are defects in the lens design.This problem is even more evident when working with metallic reflective materials.

The fourth key parameter is material compatibility.

The secret of metal lenses.

The coating on the lens used for stainless steel is completely different from that for plastic.One customer who was making kitchen utensils complained that the markings were turning yellow, and it was discovered that the lens didn't have an anti-reflective coating, and that 10 % of the laser energy was being absorbed by the lens itself.

The fifth critical parameter is thermal design, which is often overlooked.

When working continuously for over eight hours, the camera can heat up to 60 ° C.A good heat dissipation system must have three elements: a ceramic mirror seat, a circulating airway, and a temperature sensor.Last summer a factory used a poor quality lens, and the focal length shifted due to thermal expansion, resulting in the entire batch of workpieces having to be reworked.

Three steps to selection.

1. Take samples and do destructive tests: Print 2,000 times and see if there is any degradation in the results.

2. Don't just look at the maximum value: Focus on the actual range where 90 % of the energy is concentrated.

3. Ask suppliers to provide a temperature drift curve, which shows the change in focal length for each 1 ° C rise in temperature.

Finally, don't be tempted by bargain prices on off-brand lenses.We have seen too many cases of people trying to save money and ending up losing more in the long run. After all, the cost of lost production time due to a camera malfunction is more than enough to buy several original parts.