With the variable speed controller on and the proper level of parts in the bowl, set the dial at 35% to 40% of the input voltage.
Some parts movement should be detected at this point. If the feed rate is too slow, increase the controller setting slowly until the desired feed rate is attained. When 80% of the input voltage has been used without reaching the desired amplitude or there is excessive or sporadic vibration, check for interference points where something may be contacting the bowl or base drive unit, then follow these tuning techniques to achieve maximum efficiency:
Loosen a bolt on any one of the spring clamp blocks (preferably a lower bolt), very gradually, until the unit either speeds up or slows down. If the unit speeds up, it is over sprung. If the unit is over sprung, the thinnest spring from two opposing hangers must be removed. When replacing the springs, they must be torqued as specified in “Base Unit Torque Requirements.”
If after this change, there is an under sprung reading (if unit slows down when a bolt is loosened), thinner springs must be added back to the two opposing hangers. IMPORTANT! To maintain consistency, even feed motion, the number of springs in opposing spring packs must be equal.
The base unit should be slightly over tuned, but the degree of over-tuning must be established. An over tuned condition is a good indication that all bolts are tight and all springs are in good condition.
Springs tend to work-harden on a base drive unit that has been- in operation for a period of time, causing it to be over tuned. The same procedure as described in (1.) should be used to determine if this condition exists.
If a unit indicates that it is still under sprung after a spring has been added, check for a spring that may be cracked or broken. This usually happens on the bottom portion of the spring, near the spring clamp hanger. In some cases, the crack cannot be seen because of paint or because it may not be all the way through to the point where it is easily visible it should be removed and inspected closely for hairline cracks.
Make sure the bolts are long enough to fasten the springs to the spring hangers. For example, if a 5/16″ thick spring has been added, there will be 5/16″ less of the threads to hold the springs. When tightened, the threads may strip and the unit will give a false tuning reading. The same also applies to the bolts holding the armature or the bowl clamp nuts. The holes for these bolts are blind, therefore if the bolt bottoms out, it will seem to be tight when it actually is not. This situation will cause false readings in the tuning process.
Another factor that affects tuning is the stretching of the bolts that fasten the springs. We use grade “5” bolts, which are specially hardened for durability to prevent this from occurring.
The tuning of a base drive unit is affected when a weld is either broken or cracked any place in the drive unit or:
(a) The mounting flange of the bowl.
(b) The track or skirts.
(c) The bottom of the return pan.
(d) The braces, pan wall, discharge area (as a general rule, these conditions will create a foreign noise and be easily detected).
Another condition, that occasionally develops and is very difficult to detect, is bolts that hold the rubber feet onto the base drive backing out, causing solid contact between the drive unit and mounting surface. This can cause the tuning to be misread. The way to check for this condition is to remove the unit from the common base plate, and lift it up so that the feet are exposed and tighten the mounting screws.
It is very important that the clamp nuts holding the bowl to the base drive are tight. When remounting or relocating a bowl on a base drive unit, use a 12″ to 15″ pipe on 9″ to 15″ units and one 36″ to 48″ long for 18″ to 36″ units. This gives the necessary leverage to tighten the bolts. (For the best results, use a torque wrench). Also, never pull a bowl out, even slightly, from the clamp nuts to line it up with an existing track. Instead, use the jack screws (for leveling and height adjustment) which are built into each LP drive unit as a standard feature. If the bowl is not level, parts may fall off or drift from the track prior to entering a selector causing track jams, misoriented parts and a loss of feed rate. A feeder must be level in order to maintain proper feed motion.
Another problem can result by omitting the thin shim (spring spacer) between the springs when they are changed or added. These spacer shims are very important. If one is omitted, it will result in an adverse effect on tuning. If a shim is not available, one should be made and installed. Don’t take the easy way out and try to get by without it. This will only cause more problems later.
The feed rate will be affected if all bolts that attach the rubber feet to the mounting plate are not securely located. These bolts are to prevent the unit from rotating on the plate. When the drive unit is securely mounted to the plate, optimum feed motion will be transferred to the vibratory bowl.
Also, make sure that the holes are drilled on center and that the rubber feet are not stretched when tightened. This will prevent tuning problems.
If the gravity or inline track is connected to the vibratory bowl, the feed motion will be adversely affected. The solution is to use an independent track to move the parts from the bowl discharge.
If a feeder bowl has “dead spots”, most often, the problem can be found by looking 180 degrees from the location of these “dead spots”. As a general rule, mass has been added without counter-balancing the bowl, the gap in the coil has been improperly set, there is a broken weld, broken spring, or a loose spring bolt. Any of these conditions may contribute to the problem.
|CLAMP NUT BOLTS
|SPRING MOUNT BOLTS
Installation & Troubleshooting for Straightline Drivers
When the vibratory straight line driver will not transmit power to the horizontal vibratory track, it is often caused by one of the following reasons:
- The power supply to the control may be inadequate.
- The cord from the driver to the control may be improperly connected or damaged.
- A fuse may be blown in the straight line driver controller.
- A coil may be shorted out.
- The gap between- the coil and armature may be out of adjustment.
- A piece part or foreign object may be lodged between the coil and armature.
- The straight line driver may be making contact with the vibratory bowl or other equipment such as the escape and placement station.
When a straight line driver has an insufficient amount of vibration or slow, sporadic or irregular parts movement, it is usually due to one of the following reasons:
- One or more springs in the straight line driver may be cracked or broken.
- It may be mounted on a base plate that is too thin which can cause flexing that will absorb useful vibration.
- The base plate may be mounted improperly, lacking rigidity. The straight line driver may be mounted on a common base plate that overhangs the machine base. (Base plates should be at least 11/4″ thick with substantial support directly under the drive unit).
- The bolts which attach the track to the aluminum top member of the straight line driver may be loose.
- The table may not be level or lagged down properly.
- There may be an accumulation of foreign material on the track surface.
- The coil gap may be improperly set. The gap should be set as close as possible without the pole faces striking (pole faces should be parallel).
- The voltage to the controller may be fluctuating.
- The straight line driver may need retuning to the power supply that is available in the area.
- The parts may be out of tolerance, have burrs on them, be bent or warped or have oil, mold release or some type of contamination on them which prevents proper movement.
- Changes of part configuration may require new track tooling and retuning of the straight line driver.
- The use of air jets presents problems when they are not set properly. (Pressure set too high or too low). Some things to look for: Is the air contaminated? Does the air line contain water or oil? If so, this contamination will accumulate on the running surfaces of the track and create a condition that will slow down part movement or actually stop it. All air to a feeder system must be dry, filtered and regulated to achieve peak efficiency. A regulator must be used, to provide a consistent flow, eliminating the high and low pressure factor, and each air jet should be metered with a separate flow control valve. Attaching rigid lines or hard plastic tubing must be avoided as it dampens vibration and will cause interference with part pressure as well as other tuning problems. Flexible nylon tubing or other soft flexible tubing should be used to prevent interference with vibration from a vibratory straight line driver.
- The vibratory straight line driver may not be tuned properly. The tuning consists of the addition or removal of springs. This balances the spring tension in proportion to the weight of the track.
- Power supply from the controller may not be the proper frequency (make sure switch on power board is in correct position for either 60 Hz, DC or 120 Hz, AC).
Procedures for Straightline Drivers
The following procedure should be used to check the tuning of straight line drivers:
- IMPORTANT! Before tuning unit, make sure there are no cracked or broken springs, that ALL bolts are tightened and the magnet pole faces are set at the proper gap. With the variable speed controller on the track full of parts, set the dial at 35% to 40% of the in-put voltage. Some parts movement should be detected at this point. If the feed rate is too low, increase the controller setting slowly until the desired feed rate is attained. When 80% of the input voltage has been used without reaching the desired amplitude or there is excessive or sporadic vibration, check for interference points where something may be contacting the track or driver, then follow these tuning checks for peak performance:
- Loosen an upper spring pack bolt on any one of the spring clamp blocks (preferably a lower bolt), very gradually, approximately one-half turn until the straight line driver either speeds up or slows down. If it speeds up, it is over sprung. If it is oversprung, the thinnest spring from the spring pack with the most springs must be removed. If after this change, there is an under sprung reading (if the unit slows down when a bolt is loosened), thinner springs must be added back to the spring pack with the least number of springs. It should be slightly over tuned, but the degree of over-tuning must be established. An over tuned condition is a good indication that all bolts are tight and all springs are in good condition.
- If the straight line driver indicates that it is still improperly tuned after a spring has been added, or removed, repeat #1 until the proper tuning is achieved (it is not necessary to have the same number of springs in each pack, however, they should be distributed as evenly as possible).
- Make sure the bolts are long enough to fasten the springs to the spring hangers. If springs have been added, there will be less threads to hold them. When tightened, the threads may strip and the unit will give a false tuning reading. Most of the holes for these bolts are blind, therefore if the bolt bottoms out, it will seem to be tight when it actually is not. It is very difficult to check the tuning of a straight line driver until this factor has either been ruled out or remedied.
- Another factor that affects tuning is the stretching of the bolts that fasten the springs. We use grade “5” bolts, which are specially hardened for durability. Make sure that all spring bolts and “hold down” bolts and nuts are tight.
- Another problem can result by omitting the thin shim (spring spacer) between the springs when springs are changed or added. These spacer shim are very important. If one is omitted, it has an adverse affectairline tuning cannot be properly evaluated. If a shim is not available, one should be made and installed. Don’t take the easy way out and try to get by without it. This will only cause more problems later.
- If a vibratory straight line has a dead spot at either end, it may be eliminated by placing extra spring spacers between the spring and the casting (upper spring pack). If the front end of the driver is running too slow add spacers under the lower end of the front spring pack. If the rear of the driver is running too slow add spacers under the top end of the rear spring pack. Sometimes by changing the number of springs in the lower spring packs (isolation spring), the feed motion can be improved. It also becomes necessary sometimes to change these lower springs to fiberglass material.
- The above information pertains to: Vibromatic Feeder Bowls – Vibratory Feeder Bowl systems including Vibratory Feeders, Stainless Vibratory Feeder Bowls, Polycast Feeder Bowls, Parts Feeders, Vibratory Drive Units, Vibratory Tracks, Orienting Rolls, Feeder Bowl Controls, Bulk Hoppers, Floor Feeders, Sound Enclosures, Assembly Mechanisms, Escapements, Centrifugal Feeders, Stepper Feeders, Automatic Screwdrivers and part handling systems offered to serve the automation industry worldwide.