Deep Laser Engraving of Mold Cavities

Is Laser Engraving a Better Option for Engraving Mold Cavities?

Laser marking and laser engraving technologies are emerging in the moldmaking industry for use in machining mold cavities. Mold makers know that machining small cavities in molds is difficult and time consuming, and extensive hand polishing is usually needed to complete the job. The task is made more difficult if the mold has already been hardened or made from pre-hardened steel.

Deep laser engraving provides an alternative non-contact machining process that is effective on hardened tool steels and able to access difficult to reach locations. It complements traditional CNC milling and electrical discharge machining (EDM) processes.

What Is Deep Laser Engraving?

Deep laser engraving is generally considered to be a machining process that removes up to 30 thousandths of an inch of material. It is frequently used to add detail to molds such as patterns and features or to add identification marks. It's different from laser marking in that material is removed from the surface of the material.

Laser engraving uses higher powered fiber laser systems that are typically used for laser marking and engraving. The system uses engraving software as well as a range of motion control devices for precise control, and has the ability to engrave flat and contoured surfaces.

Application in Molds

The major benefit of laser engraving solutions is that it will work wherever there is line of sight to the point to be marked. If you need to put identification marks at the bottom of a tool for making a plastic pin, it’s a relatively simple task to mount the mold in the laser and make the laser engraving. Deep laser engraving can be used for small and complex parts that are impossible to reach with mechanical engraving equipment.

Comparable Processes

A significant benefit of using lasers for engraving molds is that it works equally well on hardened steel surfaces. In this context, it has similar properties to EDM, also known as spark eroding. However, it's generally faster, easier to set up, and requires no expensive consumables such as electrolyte and electrodes.

On the other hand, if the volume of material to be removed is significant, then conventional CNC milling may be faster and or more effective.

Benefits of Laser Engraving

Deep laser engraving can reduce costs and expand the scope of work performed by tool and die makers. Some of the benefits of laser engraving include:

• Replace milling and EDM machines: Laser engraving can replace conventional machining methods for small cavities and reduce overall mold costs.
• Long life: Laser components last longer and require less maintenance than EDM and CNC milling machines.
• Surface finish: Laser engraving gives a better surface finish that usually does not require hand polishing.
• Heat-affected zone: Laser engraving has a lower impact on the surface hardness of molds and avoids the risk of micro-fracturing that exists with EDM.
• Cost: Running costs are much lower.

Limitations of Laser Engraving

To a large degree, laser engraving complements rather than replaces EDM. The choice depends on the amount of machining needed and the mold design. Likewise, lasers cannot replace a milling machine that has a higher material removal capacity. However, a combination of all three types of machining may represent the most efficient way to manufacture molds, especially taking into account the laser's ability to achieve an excellent surface finish.

LaserStar Engraving Systems

Lasers have demonstrated their usefulness in mold repair with their ability to successfully weld fine features while providing an excellent finish. Laser engraving takes this a step further by providing mold makers with a cost-effective method of engraving and modifying molds that is faster than comparable processes. If you are interested in lasers for deep engraving, contact us through one of our National LaserStar Centers and our staff will arrange a demonstration.