I’ve spend time searching the Internet looking for laser alignment systems, used for aligning machinery. In particular sawmill machinery or equipment. I’ve had virtually no success. I have found lasers for medical, hair removal and skin rejuvenation. All kinds of lasers. A number of alignment tools for a number of specific applications. Diode lasers, for coupling alignment and V belt sheave alignment. Nothing on simple sawmill, machinery alignment.
In the late 1970s or early 1980s there was a company from Portland Oregon selling laser alignment systems to sawmills. Almost every sawmill that was trying to improve quality bought a system. There was some problems with this system. Which I believe really hurt the concept badly. The laser light source was crude with a projected dot which was very fuzzy. A light detection device which was not very accurate. Four cells in a holder which were suppose to detect the light with accuracy of .001″. A comparison of how the light was detected by these four cells, was transferred to a hand held display which displayed a bar graph of lights right left, up/down.left from the center of the four cells. The idea being if the light was centered equally between all four cells the display would be display zero. As the light hit more of a particular cell it would light up more bars on the display. If the light hit more than two cells at the same time, the display would show that. in essence, high and right as an example.
However if face of this holder was dot perfectly plumb or square, the light hitting the face would elongate. Making measurements very inaccurate and unrepeatable from one set of measurements to the next. As part of this system, was a prism which was to be used to establish square. The prisms were crude and very inaccurate.
In the late 1980s, some major improvement were made. A set of lenses were add to the front of the laser. Which made the dot projected adjustable and very clean over long distances. The four cell light sensor was change to be a photo cell with thousands of lines of resolution. A filter which allowed only the hot center of the laser dot to be detected. Eliminating the elongation of the light, if the detector was not plumb or square to the light. A processor which received the information from the detector. The ability to make any position of the detector zero. A comparison to that zero, right/left and up/down. A pentaprism mounted on an adjustable plate, allowing accurate measurements for square and 360 degree capability.
Over time a number of jigs, holders and attachments were designed to make the use of this laser alignment system quick, accurate and easy to use for aligning any and all sawmill machinery. An accurate level was added to the top of the laser tube. Which allowed the light to be set level. Initially, the light was set in line with two references on a whatever plane the machine happened to be on. With the addition of things like a tripod stand to support the laser, uses for alignment became endless.
Some cautions and thing to be aware of when using lasers for alignment purposes. Heat or temperature changes of the laser itself. The canister housing the laser tube and power supply changes as it warms up. Allow the laser to get up to temperature before initial set-up. If the laser is mounted outside in the elements of winter for example. These temperature changes can effect the light. Continually check the light has not changed. This is simple to do. When final set up is complete. Place some sort of target or mark where the laser dot is. Such as drawing a circle around the laser dot, where it hits a wall, or another machine beyond the machine to be aligned.
Another thing which will effect a laser’s accuracy is heat waves or cold breezes. The light emitted from the laser travels through the air so if the air move so does the light. Simply close any doors or holes which may create cold drafts, or waves of heat. Direct sunlight or fluorescents will affect the light sensor’s ability to detect the laser. Pick-ups or light sensors will come with a shield to hold out unwanted light sources. If readings are not steady. One of these items will be the reason. With these things in mind a laser is an easy to use, extremely accurate tool for aligning sawmill, or similar machines.
I believe there is still a lack of faith or belief in lasers for alignment in the forest products industry today. Even sawmill equipment manufacturers. OEMs which provide very accurate machining and fabrication specifications. Still use a wire, tape measure or scale rule and a hand held level or sometimes a transit to install and align machinery to cut quality products. Another advantage of using a laser is you can walk or drag tools, such as air hoses or welding cables through the beam without effecting the position of the light.