Centre point and offset error adjustments

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Centre point and offset error adjustments Centre point saws must have the edge of the blade lined up with the centre of rotation of the angle movement.

1 Centre point and offset error adjustments Centre point saws must have the edge of the blade lined up with the centre of rotation of the angle movement. If this doesn t happen then the length that you cut will vary as you change the angle. When a saw is new, this mechanical adjustment is correct, and the length will be correct no matter what angle you set the saw to. Once the saw gets older, and is used a bit more, this adjustment moves. On the larger type saws, this adjustment is very difficult to loose (you may have to hit the saw with a forklift to damage it) while on others, all you have to is jam a block in the blade. You ll know that these adjustments have moved if the length is correct at angles closer to 90, but is incorrect at lower angles, with a larger error as the angle goes towards 0 degrees. There are two ways of the fixing the problem once this adjustment has moved. You can readjust the saw mechanically (which is time consuming, requires skill and hard work) or you can adjust the software on the computer so that the length will automatically change to compensate for the error in length.

2 Make sure that the saw is calibrated perfectly before you start these checks. There are two adjustments that you must set before the saw will cut correctly again. They must be done in the correct order. You must set the Offset, then the Centre point. The offset adjustment is a measure of how far in front of, or behind the fence the centre of rotation is. This is checked by making two cuts on a piece of the timber (one of 45º and one at 135º), then tracing a line along the edge of the cuts until you find the intersection. Move the saw by hand to 45 (push the emergency stop in and pull the saw around). Hold the timber up against the fence and pull the saw about half way through. You now need to move the saw to 135 and do another similar cut. It is very important the timber is not moved between cuts. If necessary, get someone to help you. Offset Error Fig and 135 cuts in timber, with offset error shown. This is for left hand automation setup (stop on left of saw), and shows a positive error.

3 Offset Error Fig. 2. Negative offset error. If this is the type of result you get, you will need to trace the cuts onto another piece of timber (as described below) in order to measure. You now need to trace the edge of the cut that is on the length stop side of the blade. That is, if the length stop is on the left side of the saw, you must trace the left hand side of the both cuts. DO NOT trace the left side of one cut and right side of the other. You will find that the resulting timber should look like either fig. 1 or 2. The only exception to this will be if the cross point of the cuts is exactly on the edge of the timber. If this is the case, then there is zero offset error (you will still need to check the setting on the computer because it is possible there was originally an error that has now disappeared). Carefully measure the distance from the cross point to the edge of the timber. If you have a negative error (fig. 2) you will need to butt up a piece of timber to the original, and using a pencil and ruler, extend the line of the cuts onto the new piece. You should now be able to measure the negative offset. Depending on your version of the software, you will need to go to the settings screen, or select option 8 after pushing F4. If you have a version older than , you will need to go into the settings screen (F4, Enter, Enter, Enter, password, then YES, Enter). Input your measured offset error. Remember to put a - in front of the number if it is a negative error, and input a zero if the cross point was right on the edge of the timber. If you are using imperial units, you can enter the error in decimal feet or feet-inchessixteenths. If you have a negative number, and you want to use feet-inches-sixteenths, you still need to put the - in front of the number that you enter. Now that you have set the offset error, you will need to set the Centre Point error.

4 The Mango Automation software has an automatic centre point adjustment routine. If you have software that is older than version , you will enter this routine by going to the settings screen and press the enter key to get down to the do you want to adjust the centre point error box. Arrow across until Yes is highlighted, and hit the Enter key. If you have software that is newer than this, then you enter the centrepoint screen by pushing the F4 button, then pushing the number 8 button. This will put you into the offset error box. Once you have entered the offset error (see above), push enter. This will load the centrepoint screen. Select a straight bit of timber about 2-3m (about 10ft) long. Ensure that one end is nice and square. Measure the length of timber, and enter into the what length of timber are you going to use box, the length rounded down to the nearest 100mm. i.e. if you measured 2880mm, then enter Hit the enter key once. This will set the angle and length. The angle will set to 10 degrees and the length will set to the length that you entered as the stock length. On some versions of the software you need to answer YES/NO to let the computer know that it has set to the correct length. You will know that you have this version if you see a YES/NO box just below the Stock Length box. If you have this version, push ENTER on YES if the length and angle set to the correct positions (i.e. both readout boxes are green at the top of the screen), or push NO if they did not set up correctly. Hit Enter twice more to set the saw so that it includes the length error currently set in the computer. You have got it set up correctly if the length is shown in the grey box at the top of the screen. If you have a version of the software that doesn t have the YES/NO boxes, then as soon as you push ENTER, the length and angle will move to the required positions. If they don t, release the stop button and push ENTER again. Put the square end of the timber up against the stop, and make the cut. You do not need to cut right through the timber. You only need to make a cut that is full depth of the timber, not full width. Measure the timber length, and put in the error (see the screen instructions on the screen if in any doubt about how to enter the length error). You must compare the length of the timber that you have cut with the target length on the screen (in the Required Length box) Repeat the process until you are happy with the accuracy of cut. Remember, every time you do a cut the length will shorten up by 50mm (2 if you using imperial units) so that you are always cutting fresh timber. Every time you hit enter after changing the length error, the new error setting is saved in the computer. Once you are happy, press F1, and exit the screen.

5 ! If you are an American (using imperial units), you have a bit of a harder job. The accuracy required for this test is better than 1/16 th. That means we can t use feet-inches-sixteenths to enter in our errors. We have to use decimal feet with 6 decimal places of accuracy. This is a bit confusing, time consuming and very prone to errors (you have to keep converting to decimal feet before you make any changes, and people get the conversion wrong) There s a cheats way of getting the job done. You can set the software to think that it s working in metric, load an imperial job (just one your normal jobs), then go into centrepoint error screen and make all your changes in millimetres. There s no 6 decimal place numbers to have to deal with and you can make all the changes without using a calculator. The Imperial switch (to switch the software from metric to imperial and back again) is in the initialization file for the machine. This file is called C:\Program Files\MangoTech Automation\MangoTrussSaw.INI. Double click on this file on Windows Explorer and it ll open up and you can read it. About ¾ of the way down the file you ll see a line that says Imperial = 1 You need to change this to Imperial = 0. Only change the 1 and 0, and make sure you keep the number in the same place (don t move it next to the = sign..i.e. =1 or =0. It needs to be = 1 or = 0.note the space between the = and the number). Once you have made this change, go back to the MangoTech software, click on the x at the top right corner of the screen and then restart the MangoTech software again (not the whole computer, just the saw software). This will make the change the software (ie change it to metric). Then load a job, make sure the calibration is correct (go into the calibration adjustment screen, you don t have to recalibrate, just check it), and go into the centrepoint error screen and make your changes in millimetres. This may sound a little complex and if you feel that s not what you want to do, then you can still make all the adjustments in imperial (i.e. you don t have to make any changes to the INI file.it s just our suggestion because we find the decimal feet so hard to use) If you have any trouble, please call or Australian Ph support@mangotech.com.au

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