Owners of xTool D1 or D1 Pro laser series are likely familiar with the brass cap shown in the image, commonly known as the "lens" in the community. Since it is not advisable to expose a lens element directly to the external environment, the protective lens cap is an essential accessory.

To avoid distortion, discoloration, or crazing of the glass surface, regular cleaning and replacement are necessary. In this article, we aim to clarify any mysteries surrounding this topic.

Why do You Need to Clean the Protective Lens Cap

The lens protective cap is a consumable item. It is constructed of brass and contains a piece of quartz glass that measures up to 7 on the Mohs Hardness scale. It is rated for high temperature and thermal shock resistance.

During laser operations, there may be times when dust, smoke, or soot comes in contact with the protective glass. During use, those contaminants may distort, discolor, or craze the optical glass surface. In extreme instances, the glass itself may crack.

You can see some minor damage to the optical surface in the photo. When the glass becomes sufficiently affected the laser beam may drastically lose efficiency, or create unwanted effects.

*Scorched lens under the microscope

How to Maintain the Lens Cap?

It is important to keep the surface of the optical glass as clean as possible. Many times this distortion can be removed by cleaning. xTool recommends the use of anhydrous ethanol for cleaning. Also optical cleaning cloths should be used. Other fabrics may damage or scratch the quartz surface. 

Many users may also find that 91% or higher isopropyl alcohol can be an effective cleaner as well. In many cases the effected area (as depicted in the photo above) can be almost completely removed. Some pressure may need to be applied for thorough cleaning.

If the contaminants or distortion cannot be removed the protective cap should be replaced. 

Many other manufacturers do not offer the protective lens cover as a consumable item. If their lens cap glass breaks your machine is down until a warranty replacement is obtained. Fortunately xTool does offer this item as a consumable. The xTool D1 Pro 20 watt kit I received contained one spare cap. Caps can be purchased from the xTool accessory area. Additionally, the xTool parts kit for the D1 series contains a spare cap.

How to Replace it?

Some users opt to purchase optical glass from third-party sources and only replace the glass in the cap when it sustains damage. Although this may result in saving money, it is likely that such an action could cause optical concerns.

Moreover, some people suggest that using a laser without the cap installed is possible. While technically correct, it poses the risk of permanently damaging the lens, which would necessitate the replacement of the entire laser head assembly. So,we strongly recommend using the authorized xTool replacement protective caps. 

Hopefully, we’ve cleared up some of the mystery surrounding the protective lens cap. Its primary function is to protect the optical lens found in the laser head assembly. It is a consumable item that every D1 series owner should have on hand to prevent downtime.