Matching the Proper Strapping Machine to the Task
Choosing the correct strapping machine for your packaging application is an important decision to not take lightly. No matter how exacting your QC (quality control) is, and how convenient your shipping is, if the final shipment doesn’t get packaged securely and arrive in the time you quoted, it will not appease your client’s expectations.BASIC TYPES OF STRAPPING MACHINESManual Strapping Kits ($$$$$) These kits are for the operation that requires strapping on a very limited basis. Kits usually come with at least one roll of strapping, a tensioning tool, buckles / seals & they should include instructions, if not be sure to ask your distributor to acquire you some.Semi-Automatic Stapper ($$$$$) Otherwise known as a "table top" machine, semi-automatic strapping machines are the entry level strapping machines for low volume operations. They are usually about the size of a small desk (36” x 24” x 30” high). With a semi-automatic machine, the operator takes a loose end of strap that has been fed from the machine, loops it around the package, and hand feeds it into the strapping and sealing area. The machine automatically tensions the strap according to a per-set tension; heat seals the ends together, and feeds out a pre-set length of strap for the next cycle. Semi-automatic machines are relatively inexpensive, and can be very versatile. They can be used as both the primary strapper in low volume operations, and for back up, or off line strapping.Arch Machines ($$$$$) Arch machines are more automated than semi automatic machines, butstill require an operator to position the package, and press an activation button (or foot switch) to start the strapping operation. With an arch machine, the strap travels around an “arch” creating a loop before activation. When the operator activates the strapping sequence, the strap tensions, heat seals, and pre-feeds the strap for the next cycle. Many Arch machines can also be activated by a photocell or limit switch built into the top. While these devices will automatically activate the cycle, the operator will still position the package for strapping and remove it when the cycle is completed. Arch size is critical with an arch machine, since package size is limited to what will fit under the arch. Arch machines are much faster than semi automatic machines, less operator dependent, and, of course, more expensive.Fully Automatic Machines ($$$$$) Similar to arch machines, fully automatic strappers have builtin conveyor systems to carry your product through the strapping machinery, and are activated by an automated device, usually a photocell. Fully automatic machines do not require an operator. As with arch machines, they must be sized properly. The additional features on a fully automatic machine will drive the cost up, depending on features and arch size.SPEEDYour strapping application should match the production and packaging rate of the rest of yourprocess. You don’t want bottlenecks at the strapping center, nor do you want to pay for speedthat is not necessary. Speed in general, will mean increased costs. Before you begin "kicking tires", make sure you know how much speed is really needed.STRAPPING RATES
- Semi-Automatic Machines: 10-15 straps per minute, depending on the skill level of the operator.
- Arch Machines: 30-70 straps per minute.
- Fully Automatic Machines: 30-70 straps per minute. Important factors to consider with fully automatic machines will be:
- Total strap rate: including transportation time through the conveying system.
- Conveyor speed: must be as fast as your existing conveyors, if not faster. Don’t design a strapping bottleneck into your product flow.
FEATURES YOUR OPERATION DEPENDS UPONThere are a few options available on semi automatic machines, but they are usually applicable tospecific types of applications such a very low or high tension. If you are considering a semi-automatic machine, and you need these features, they are available in different models at a modest to a premium cost. There are, a host of options available on both arch and fully automatic units. Selecting which are appropriate for your application will determine the machine you need and your purchase cost. More features will translate into a higher initial cost, but may also mean lower total operating costs.COMMON FEATURES
- Auto Feed – Auto feed enables the operator to load the strap coil on the dispenser, and by pressing the feed switch, have the strap automatically thread through the machine. Without autofeed, strap loading can be extremely cumbersome. Do you need it? If you are changing a coil every month, it’s not necessary. Changing a coil every day, and it definitely worth the investment.
- Jam Free Auto Re-feed. This feature will reefed the strap and reset the strapper in the event of any jam or misfeed. If you don’t have it, you will have to manually re-set the machine if a jam occurs.
- Loop Ejection - If your strapping machine is activated without a package in it. Without loop ejection, you may have to pull it out of line for a manual re-set. With this loop ejection feature, your machine will “kick out” a small loop and reset itself for the next cycle. The loop ejection feature is more suitable for high volume applications.
- Arch Size – Conventional wisdom tells you to use your largest package as a guide when sizing your arch. However,if your largest package is a small percentage of your total volume, it may be more cost effective to size your arch for your largest VOLUME package, and strap your larger packages off line with a semi automatic strapping machine, which is not limited by arch size. Very large arches get quite expensive, and the actual cost a smaller arch and a semi automatic machine together, may be less than the cost of an extremely large arch. A second semi-automatic strapper also gives you a back up in the event your primary unit is down.
- Strap Width – Common sizes are 7/16", 1/2", 5/8" & 3/4". Size the strap first based on package weight, handling characteristics, and shipping methods. Buy a strapping machine that runs the strap size you have selected. Strapping machines are set to run a certain width, and changing that, if it can be done, requires considerable time and expense.
MAINTAINING A STRAPPING MACHINELike any piece of industrial equipment, a strapping machine will require a certain amount of maintenance. Smart maintenance procedures on a strapping machine:
- Documented preventative maintenance
- Checking belts
- Examining switches
- Inspecting connections
- Looking over parts to see wear
KEYS TO MAXIMIZING UP TIME
- Use GOOD strap. For consistent operation you need strap that is consistent in width and gauge, and has minimal camber (curve). Many machine problems can actually be strap problems.
- Dust from Polypropylene and Polyester strapping is the enemy of strapping machines. A certain amount of dust is normal. To minimize its impact on the strapping machine, blow it out with compressed air, daily.
- Stock Critical Parts. Every manufacturer or distributor should be able to give you a list of recommended spare parts. Even if you get overnight parts service, stocking critical parts is recommended. Most repairs are relatively simple, and having the parts can get you up and running in minutes rather than hours. Select the right strapping machine and maintain it properly, and you will build a solid foundation for years of trouble free, efficient and cost effective performance.