While it would be impossible to cover every troubleshooting scenario for every packaging machine in production, there are some recurring issues that have arisen over the years. Some of the more common problems do not always have an obvious resolution, though more times than not a simple fix will have the equipment running production consistently and reliably in no time at all. Below are some of those common problems, along with the typical fixes.
1. Inconsistent Filling
Different filling machines, of course, use different filling principles and different types of nozzles. So inconsistent filling can come from different sources depending on the type of liquid filler being used on a packaging line. In general, however, the source is often either an incorrect set up of the filling machine or wear parts that need to be replaced.
During the set up of the bottle filler, nozzles must be positioned correctly over the bottles. Some nozzles, such as those found on an overflow filler, will dive into a bottle and create a seal. The compression on these nozzles must also be set correctly to achieve consistent, level fills. Operators experiencing inconsistent filling should first check the physical set up of the equipment, ensuring nozzles are lined up with the bottles and diving correctly. A power conveyor system will normally move bottles into and out of the fill area as well, with the assistance of an indexing system, such as entry and exit pins, a star wheel or some other type of system. The operator should check the guiderails to ensure bottles are consistently lining up in the correct position, as well as the indexing system to verify that bottles are stabilized while in the fill area.
Automatic filling machines will normally be controlled by a PLC, accessed using a touchscreen interface found on the control panel of the machinery. The operator interface will allow the user to set fill times as well as delay and duration times for components such as the head dive, pump, indexing and more. Normally these machines will come with settings for individual bottles pre-set on a recipe screen. Inconsistent fills can arise from having incorrect fill times, delay times or duration times, or from entering the wrong recipe for the product and bottle being run. The operator should also double check to ensure all the settings are correct. As a side note, it is always a good idea to keep a hard copy of all times and settings in the event of damage to the PLC from a harsh environment, a power outage or other unforeseen circumstances.
Once these checks have been completed, if inconsistent fills continue, any wear parts found on the packaging machine should be inspected and replaced if necessary. Many nozzles will include O-rings or seals that will, over time, require replacement. These O-rings, seals and similar components can let air into the product pathway at various points, leading to the inconsistent fills. In fact, operators should also inspect and tighten hose clamps connecting tubing to the machine along the product pathway, as something as simple as a small amount of air entering the pathway at the tubing can cause inconsistency. Running through these simple checks will lead an operator to the solutions for problematic fills a majority of the time.
2. Inconsistent Capping
Once a packaging line is filling consistently, the last thing an operator wants to deal with is inconsistent capping, which can lead to cross threads, loose caps or impossible to open tight lids. As with the filling machines, capping equipment will differ based on the type of cap and seal being used. However, some simple inspection of set up and wear parts will once again usually lead to the solution.
The capping apparatus, whether spindle wheels, a chuck head, snap on belt or other device, must be properly placed to reliably and consistently seal containers. The operator should first check the capping apparatus to ensure that caps are being contacted at the correct position to create this reliable and consistent seal. Adjustment will normally involve simple tweaks to the height and width of the apparatus, and some trial and error may be involved. If it appears that the capping apparatus is properly located, attention should be turned to any components used to stabilize the bottle and cap. Gripper belts, guide rails, cap tongues and cap stabilizer bars will all be used to ensure proper sealing. If bottles or caps are not stabilized, the movement can play havoc on the capping process. Inspect these stabilizing elements to ensure bottles and caps are secure throughout the sealing process.
Capping machine wear parts are generally contact parts. Spindle wheels spin down screw on caps, snap on belts apply pressure to snap on caps. Gripper belts contact the bottle to stabilize it through the capping process. As these parts wear down, they become less effective. Operators can inspect the wear parts on their specific bottle capper and make replacements as necessary. Again, going through these simple steps will solve inconsistent capping more times than not.
3. Bottle Tipping and Spills
The key to solving bottle tipping and spill issues is to locate the source. If the tips or spills are happening at a single location, an operator may need to return to the set up inspections described above. An improperly positioned indexing system on a filling machine, for example, may lead to tipping bottles. Incorrect fill times may lead to spills. Gripper belts squeezing to tightly on a bottle may push product out of that bottle before a cap is properly tightened at the capping and sealing station. If bottle tipping or spills can be pinpointed to a single machine or location, inspect the machine and make adjustments as necessary.
If seemingly random tips or spills occur along the packaging line, the transfer system, normally a power conveyor system, may be the problem. The operator should inspect the conveyor belting, as well as any transfer locations, for damage. A crack or missing piece of belt can cause bottles to become unstable while moving along the conveyor. Damage to a transfer plate between conveyors may cause bottles to jump or tip as well. Finally, the operator can verify that the conveyor speeds are correct and consistent along the packaging line. If one or more conveyors have inadvertently been slowed down or sped up, the exchange from one speed to another may cause tipping or splashing and spills.
4. Machine Components and PLC Settings
From time to time, the packaging process as a whole will function correctly, but a single component of a machine will not perform. For example, drip trays and head dives on filling machines are common culprits. Normally, one of two settings in the PLC will solve such issues. The operator interface for the PLC will almost always include a Manual Toggle Screen, used to control certain components of the packaging machinery during set up of the machine or while performing maintenance. The drip tray can be retracted under the Manual Toggle screen to keep it out of the way during set up or maintenance. However, if the setting is not returned to Auto before beginning production, the drip tray will remain retracted. The first settings to check when a single component is not working correctly are those found in the Manual Toggle screen of the operator interface, set the component to Auto if it is not already in this position.
The Set Up screen on the operator interface also includes settings for certain components of the equipment. For example, vision systems on packaging machinery can usually be set to read normally or inverted (depending on the type of bottle being used, transparent versus non-transparent for example). If vision systems or other components on a packaging system are not working correctly, the operator should visit the Set Up screen to ensure the component is enabled to work correctly with the packaging and product.
While these simple fixes will solve more issues than not, there are always those rare occasions when a solution evades discover. As packaging equipment is almost always manufactured for the specific project for which it is being used, the operator should always have the manufacturer to fall back on. So if all else fails, pick up the phone and talk to a Packaging Specialist to get production back to the smooth, reliable and consistent process that is desired.