12 Tips for Choosing the Right Bundler for Your Application

The variety of basic strapping machines, aka bundlers, banders, or strappers on the market, can be confusing for buyers. Defining needs relative to the choices available can help buyers select the best solution for the application in question.

Consider these questions first and then go through the 12 tips below to help guide your decision:

• What is your current process?
• What is the end goal or what are hoping to achieve with a new strapping machine purchase? 
• Ready to automate your process?
• Need to improve your throughput?  
• Existing strapping machine not keeping up or downtime has become the norm rather than the exception?

1. Manual, Operator Cycled, or Fully Automatic?

Manually operated/archless strappers require an operator to insert a pre-fed length of strap into a slot to activate the sealer to tighten, cut and seal it around a package. They are appropriate for low volume or occasional strapping requirements.

Operator cycled/walk-up machines include a strap track or arch that guides the strap around the package, limiting operator tasks to moving the package through the machine and initiating the strap cycle via a footswitch, pushbutton or sensor. Throughput of 10-20 packages per minute may be achievable with these units.

Fully automatic bundlers typically include automatic roller or belt powered conveyors to transport product into position for strapping, with automatic package positioning and strap placement. Throughput capability for single machines varies by manufacturer and is a function of conveyor speed, track and package size, typically in the 20-50 package per minute range.

2. Bottom or Side Seal? What are the differences and benefits?

Bottom seal strappers have the sealer positioned under the table and place the seal on the bottom of the package. Seal position may be in the center of the table or offset to one side. One or the other may be an advantage depending on operator location or package position on automatic conveyors as packages enter the strapping zone.

Side sealers may be an advantage for packages that enter the strapper aligned with the conveyor side rail, where it is convenient for an operator to position the package against the sealer face or where it is desirable to keep the seal off the package bottom where it might be damaged during handling. Access to the sealer for cleaning and maintenance may be more convenient with a side sealer in systems with wide strap tracks.

3. Corrosion resistance – is the working environment damp?

Machines manufactured with stainless steel and other corrosion-resistant features are available from some suppliers in semi-automatic, operator cycled, and fully automatic models, in bottom or side seal configurations. These are good choices for cold and/or wet environments like those typically found in meat, poultry, and seafood packing plants.

Certifications or ingress ratings for stainless steel machines:  Machines that are IP56 certified are impervious to penetration by dust, water, solid objects, and provide protection from splashing water, hose driven water and corrosion important where the processing line is located in a dirty, wet, and/or cold environment and the machine will need to be pulled out of line for frequent cleaning.

4. Track size considerations

The track should be large enough to comfortably pass the largest package to be strapped, but not larger than necessary since cycle times are affected by the size of the track and products to be strapped.

5. Would optional features improve finished package quality?

Compression can add consistency to strapped bundles of flat stacked products like knocked-down boxes, prevent curling of soft products like magazines, newspapers and linens, and help close telescoping cartons. Compression devices may be electrically or pneumatically driven.

Bundle Squaring may benefit loosely stacked product bundles such as knocked-down boxes, magazines and newspapers. Squaring may be via fixed guides, package stops or powered squaring devices improving side to side and/or front to back alignment.

6. What is the speed/throughput requirement?

Throughput speeds vary by manufacturer, model, track size, package size, transport speed, and package spacing. Compare published speeds with package characteristics and operational requirements such as cross-straps, multiple parallel straps, or specific leading and trailing edge straps. Best to have some excess capacity to handle peak production.

7. Are multiple machines needed?

If production levels are too high for a single fully automatic machine, options for higher throughputs include multiple machines/lines and integrated tandem systems.

Multiple lines increase throughput capability in proportion to the number of machines installed, while requiring a like increase in floor space needed.

Tandem systems align two similar machines in series with integrated conveyor and controls that optimize product flow. Tandems typically offer about a 50% increase in throughput potential vs a single machine and include automatic switching to single machine operation if the other is down for any reason. Tandems require a small increase in floor space to accommodate the second strapper compared to multiple strapping lines.

8. What sealing technology is best for the application?

There are three strap sealing technologies used in modern strapping machines:

Heat seals insert a hot blade between strap ends to melt the interface to seal them together. They make satisfactory seals on PP strap but have limitations including a comparatively short working life, require regular cleaning and mechanical adjustment, and emit smoke that can be irritating to operators in their proximity. Heat seals are not generally used with PET strap due to smoke characteristics.

Friction seals rub opposing strap surfaces together to melt and form the seal. They also create satisfactory seals but are mechanical which has maintenance implications and the friction process creates dust, a housekeeping issue.

Ultrasonic seals are formed by applying a high frequency/low amplitude vibration to the opposing strap surfaces, forming a reliable seal that is effective on both PP and PET strap, with zero emissions. The upfront cost may be a bit higher than more mechanical systems but working life is superior. Elimination of hot surfaces is an operator/maintenance safety benefit.

9. Make sure to optimize the entire system, including strap

The machine selection exercise should consider choosing the strap that optimizes cost and package quality and finding the machine solution that best supports it. Avoid choosing equipment that requires a heavier strap than the product requires in order to run reliably.

An increasing number of bundling applications are moving to PET strapping to gain the advantages of superior feeding reliability, cleanliness, package integrity and recyclability. Heat seal bundlers do not typically operate with PET strapping due to the offensive smoke emitted during sealing.

10. Validate supplier technical support

Supplier technical support is more critical as systems become more sophisticated. Validating supplier technical support capability should weigh into the purchase decision. This includes spare parts availability, field service access and 24 hour support via phone and the internet.

11. Check references

Whatever system the analysis suggests, it is often worth asking the prospective supplier for references from existing customers using the chosen equipment and strap for the same or similar application. Check system performance and supplier support to confirm the decision.

12. Trial the solution

Prospective suppliers may be willing to agree to a live trial under certain conditions. This is a good way to get real-life insight into system performance and offers operator and maintenance personnel the opportunity to get familiar with the product before fully committing to it.

Strapping systems may not be thought of as a central part of a production process but the fact is that it fills an essential role in preparing product for shipment and can affect the customer presentation of the product as well. It makes sense to do a thorough analysis to assure making the best choice for your unique requirement.

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