1. Purpose of position
1.1 The basic of turnover. If you install circuit board by positioning pin, you must perforate first.
1.2 Limit turnover direction. Using unsymmetrical location hole can ensure only on the two conditions of not turnover or right turnover can install circuit board.
1.3 Mark holes. Double layers need carry out hole metallization and there be many holes in the copper -clad board at next install time. It’s difficult for users to distinguish top layer, bottom layer and direction, but it’s easy to distinguish if have mark holes.
2. Influencing factors of turnover
2.1 Quality of positioning
2.2 Quality of transmission part
2.3 Quantity and position of location hole
2.4 Verticality of engraving machine
3. Influencing factors of positioning quality
3.1 Generally , engraving machine software ensure positioning limited of turnover direction coincided with the direction limited at software.
3.2 Positioning bit and positioning pin. Location hole must be drilled by bit, and the bit diameter should be slightly larger than positioning pin. If the bit diameter is too large will cause accuracy reducing. But if the bit diameter is too small that positioning pin can’t be put in, forced install will also reduce the accuracy.
3.3 Positioning depth. Generally requiring the range that positioning pin insert into the platform is more than 1mm.But it is not necessary over 2mm. Too deep positioning pin will influence working life of the platform,and too shallow positioning pin will influence the precision.
4. The relationship between the transmission part quality and turnover.
The transmission part quality has great influence on turnover. Deviation situation of transmission part can even been roughly judged by circuit boards.
4.1 The quality of transmission part which horizontal direction coincided with turnover direction has great influence on turnover.
4.2 The quality of transmission part which horizontal direction not correspondent with turnover direction has certain influence on turnover.
4.3 The transmission part quality of vertical plane have almost no effect on turnover.
Take left-right turnover for example. Transmission part of X direction has the greatest influence, Y direction has less and Z direction has almost no effect.
5. The Relationship between Quantity, Position of Location Hole and Turnover.
If everything is in ideal state, there is no relationship between the quantity and position of location hole. But in fact it is not true.
5.1 Two points location. Based on the design of two points location, the best effect is at flanks in the center of circuit board. The greatest strengths is that the quality of transmission part will not cause circuit board rotation and easy to install. But the verticality problem on level of engraving machine will especially obvious, and it is easily because of users’ wrong operation so as to reduce the precision of the circuit board.
5.2 Four points location. Based on the design of four points location, the best effect is near the four angles of the circuit board.（Accurate position related to the accuracy curve of transmission part.）This method not only make horizontal fixed but also make upper and lower fixed which can effectively avoid operating error. But the undergrade instrument instead can cause rotating phenomenon of circuit board after turnover.
Take left-right turnover for example, if the height of the circuit board is 100mm.Choosing the number near 10or 90 for y coordinate can get the best effect, and choosing the number near 0 or 100 is most convenient for user operate.
6. Verticality of engraving machine
6.1 Horizontal plane verticality. If horizontal plane is not verticality, original orthogonal and ladder design will deform, then cause installation difficulty after turnover and circuit board rotation.
6.2 Spindle verticality. Location hole is drilled by bit. If spindle is not vertical, big migration must be caused.
6.3 Verticality of vertical direction and turnover direction. Many manufacturer consider that as long as the spindle is vertical, it is not important whether the z direction is vertical or not. These ideas are obvious wrong. If the z direction is not vertical, vertical drilling can’t be done and hole shape will also have a great migration.
7. Other factors
7.1 Steel resistance of transmission part. Due to some transmission parts giving consideration to load-bearing role. Exorbitant weight will take mechanical bending which can directly influence the transmission part precision then influence the turnover precision.
8. Operation notice
8.1 When install the circuit board, it should be put on the platform first, align the location hole and then plug the locating pin. Some users used to plug the locating pin on the platform and then install circuit board. It’s a wrong operation and will cause serious deviation.
8.2 When take down the circuit board, unplug the locating pin first, and then take off the circuit board. This way won’t damage the location hole on the platform.
8.3 Can’t prize too hard when take down the circuit board. Too curved circuit board can’t restore immediately which will be considered unevenness. Once this happens, need do some extra treatment.
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