Posted on April 05, 2017

We cannot express how important cleaning the sensors of an optimization scanner is. It is the easiest maintenance and probably the most rewarding that a mill can do for maintaining their optimization systems performance. The sensors must SEE the subject (board, cant or log) in order to create a proper model and to detect all the required defects. Proper cleaning and scheduling will provide your mill with more value gained by allowing the optimization system to work in an ideal environment.

Educate and Motivate your Employees

Most people view cleaning as a chore, and let’s face it, no one really cares for chores. This is why it is important to change the mindset of employees to understand that cleaning the sensors of an optimization system is a necessary process. By improving their understanding of the importance of cleaning, it will help them see the value and hopefully result in better cleaning practices.

To better understand the importance of cleaning, let’s make it more relatable. Think of the optimizer sensors as a person that wears glasses. When the glasses are dirty, the eyes have more difficulty seeing, making it hard to accurately perform visual tasks (e.g. lumber grading). By cleaning the glasses, the eyes will have clear sight with no obstructions and dirty glasses will no longer be the cause of mistakes during the visual task.

Recommended cleaning wipe

Autolog recommends using Kimwipes which are acceptable for cleaning sensitive optical components (Figure.1). This will reduce the amount of micro scratches on the sensor windows when cleaning; maintaining the quality of the sensor overtime. Also, Kimwipes don’t introduce a static charge on the glass surface, unlike other cleaning towels. A static charge on the glass surface will attract a lot more dust.

Figure 1. Kimwipes – delicate task wipes

Recommended cleaning solution

Autolog recommends the use of isopropyl alcohol (isopropanol) with a concentration of 70% (Figure.2). This alcohol is able to dissolve natural gums and resins. It also evaporates quickly, making it very attractive for cleaning glass. Also, it does not attack the anodization of the sensor casing OR the epoxy, which is used to attach the window glass to the sensor.

Note: The window is the protective glass covering the sensor components (e.g. cameras and lasers).

Figure 2. Isopropyl alcohol

Alternative cleaning solutions are harmful

Some cleaning ingredients can breakdown the epoxy resin that is used to glue the sensor windows as well as breakdown the anodization of the sensor casing. A product called Uvex clear lens cleaner is one of these products as it contains a harmful ingredient called Butoxyethanol. Other products such as Windex should also not be used as they contain ammonia which is also harmful to the sensors.

How to Properly Clean

Step 1: Clean the general area of all large pieces of debris and blow down the entire area using an air wand.
Step 2: Use the recommended cleaning supplies to clean the sensors (Isopropyl alcohol solution and Kimwipes).

Step 3: Utilizing the “wet wipe then dry wipe” method: Apply the alcohol directly to a clean Kimwipe and clean the sensors surface with this wet Kimwipe. Allow this wet surface to dry on its own; which will leave an alcohol residue on the surface. Once completely dry, wipe the surface with a dry Kimwipe; applying pressure while wiping to remove the entire dried alcohol residue from the surface. This method is the only way to ensure that no alcohol residue is left on the surface after cleaning.

Figure 3. An employee ready to clean with one wet and one dry Kimwipe.

IMPORTANT: Never spray or apply the alcohol or any other solution directly on the lens surfaces.

Cleaning Schedule

A proper cleaning schedule should ensure that the optimizer scanners are as clean as possible. It is recommended to clean during each production break or at least every 4 hours. The frequency of cleaning will vary from mill to mill, so it will be up to your team to determine how often the system requires cleaning.

Autolog helps to reduce dust

Dust and debris in a mill are impossible to avoid so Autolog has a few setups to help keep sensors clean longer.

1. We use air nozzles to blow off debris that falls on the sensors. Make sure the air supply is oil free and that the nozzles are pointed at the sensors window.
2. Before boards enter the planer optimizer, we have an air blade that blows off the sawdust and debris. Make sure the air blade is installed properly so the debris has a place to go after the air blade blows it off the board.
3. For our transverse optimization systems in the sawmill, we install the heads on a 45 degree angle which significantly reduces the amount of debris that falls on the bottom sensor. Some of our clients have found that they only need to clean once a day.

Control your environment

If dust and debris are a major problem for your optimization system, figure out if there are additional measures that can be taken to reduce the amount of dust and debris present. Maybe the blower systems can be improved to remove more dust from the environment – especially near the optimizer scanners (e.g. trimmer saw box, edger saw box, etc.). Reducing the amount of dust and debris present will make cleaning easier and help keep the sensors clean for a longer time span.

Make it a Best Practice

The good thing is that cleaning really isn’t that difficult. If you can make cleaning your optimizer systems a best practice at your mill your system will perform at its highest capability. There is no better time to start proper cleaning then now.

“Float like a butterfly, sting like a bee. The hands can’t hit what the eyes can’t see”
- Muhammad Ali

Process Expert Group