The complete Shearline XL system during commercial testing at Proud Mary, including its 18-inch drum, multi-reel cutting module, automatic feeder, twin cyclones and programmable controls.

Shearline’s current 6.5-inch trimming drum is not simply a design carried forward from our earliest machines.

It is where we returned after more than five years of designing, building and commercially testing larger drums and multi-reel trimming systems.

We built 18-inch machines, a 10-inch three-reel machine, sophisticated automatic controls, adjustable drum speeds, variable machine angles, large suction systems and automated cleaning systems.

Some of those machines performed impressively.

But the development program eventually taught us that increasing the size and complexity of one trimming machine was not the best way to increase commercial production.

The better solution was simpler: use a smaller, gentler and more controllable trimming system—and add additional systems when more production is required.

Why We Built Larger Machines

The attraction of a larger drum was obvious.

More drum circumference provided more potential cutting area, and multiple cutting reels appeared to offer a way to achieve much greater throughput from a single machine.

Shearline pursued that approach seriously.

Our development included:

• An 18-inch SL
• An 18-inch XL using multiple cutting reels
• A 10-inch Triple using three complete cutting reels
• Automatic feeding
• Large-capacity suction systems
• Programmable controls
• Adjustable machine angle
• Clean-in-Place systems

These were not concepts or laboratory models. They were full machines built and operated with real flower, including commercial operation.

The program required extensive CAD development, custom fabrication, precision reel manufacturing, automatic feeding, suction systems and increasingly sophisticated controls.

Shearline’s large-drum, multi-reel architecture was formally documented in a patent application filed on June 22, 2018, which later issued as United States Patent US11097282B2.

The 18-Inch XL: A Full-Scale Research Platform

The XL represented the most extensive development in Shearline’s large-drum program.

It was designed not simply as a larger production trimmer, but as a highly adjustable research platform. Drum speed, cutting-reel speed, suction, feed rate and machine angle could all be changed so we could study how each variable affected flower movement and trimming performance.

The machine incorporated multiple cutting reels beneath an 18-inch rotating drum, substantial suction capacity, an automatic feeder, programmable controls and an integrated Clean-in-Place system.

The XL also used a programmable self-levelling leg system that allowed the complete machine angle to be changed. This gave us another way to investigate residence time, loading and flower movement rather than relying on one fixed operating condition.

At its optimum settings, the XL could trim extremely well and produce impressive throughput.

Shearline did not discontinue the XL because it failed to trim flower.

We discontinued it after years of testing showed that the additional size, controls and mechanical complexity did not provide enough practical advantage over multiple smaller Master systems.

The same 18-inch drum is shown at higher and lower speeds. Reducing drum speed reduced how high the flower climbed, but it did not remove the greater climb-and-fall path created by the larger diameter.

What We Learned About Drum Diameter

The most important difference was flower movement.

As a drum rotates, flower travels upward along its inner surface before gravity returns it toward the bottom cutting area.

With the 18-inch drum, flower could climb substantially higher before falling.

Slowing the drum helped.

Changing machine angle, suction and feed rate helped.

But those adjustments could only influence the movement. They could not change the basic geometry that created the greater climb and fall.

When the drum was loaded more heavily, another effect became apparent.

Flower could begin circulating as a larger mass rather than repeatedly returning directly toward the cutting area. We referred to this movement as the curl.

That increased flower-to-flower contact and made loading increasingly important.

The 10-Inch Triple

The Triple was our attempt to find a middle ground.

It used a 10-inch drum and three complete cutting reels.

The expectation was that three cutting locations would produce a major increase in throughput without requiring a machine as large as the XL.

Three prototypes were built.

Testing showed that the increase in production did not come close to matching the increase in cutting hardware, suction requirements and machine complexity.

Three reels meant three precision reel assemblies, three blade locations, additional drives and adjustment systems, greater suction requirements and many more components to maintain.

The added complexity simply did not provide a proportional return.

Two of the 10-inch Triple prototypes built during Shearline’s large-drum development program.

The Real Comparison Became One Large Machine Versus Multiple Master Systems

This became the most important economic lesson of the entire development program.

Once a grower requires greater production capacity, there are two basic approaches:

Build one increasingly large and complicated trimming machine.

Or use multiple smaller, simpler systems operating in parallel.

Our experience showed that multiple Master systems were the more practical investment.

Better Treatment of the Flower

The 6.5-inch drum produced shorter and more controlled flower movement.

In our experience, that translated into gentler handling and better finished trim characteristics.

The smaller drum also produced a better relationship between usable finished flower and material removed as trim.

Because the flower was being trimmed more effectively during the first pass, substantially less hand touch-up was required afterward.

That matters economically.

A machine that processes a large amount of flower quickly but creates additional hand-finishing work has simply moved labour from one part of the process to another.

The objective is not merely to move flower through the drum.

It is to produce saleable finished flower with as little additional handling as possible.

More Production Without One Massive, Complex Machine

When additional throughput was required, multiple Master systems could be operated side by side.

That created several advantages.

Redundancy

With one large trimming system, cleaning, maintenance or another interruption can stop the entire trimming operation.

With multiple independent Master systems, one machine can be stopped while the others continue operating.

One system can be cleaned.

A trim barrel can be emptied.

A reel can be inspected or adjusted.

Production on the remaining lines continues.

That redundancy has significant value in a commercial processing operation.

Lower Capital Risk

Production capacity can also be added progressively.

A grower does not need to invest in one enormous trimming system before that capacity is required.

A facility can begin with one Master system and add additional systems as production grows.

Capital follows actual demand.

This is usually a much more sensible investment strategy than purchasing a very large and expensive machine based on future production projections.

A Smaller Overall Processing Footprint

Large trimming machines often require more than the trimmer itself.

They can require large conveyor feeding systems, larger collection systems, extensive suction equipment and additional space around the machine for operation and service.

The complete Master system is considerably more compact.

Its stand-alone automatic feeder meters flower directly and accurately into the drum without requiring a large conveyor feeding arrangement.

This allowed multiple Master systems to provide substantial combined production capacity without the enormous physical footprint associated with a single large processing line.

The Feeder Became More Important Than Drum Volume

One of the most useful lessons from the large-machine program was the importance of controlling how flower entered the trimmer.

The Master feeder does not simply replace an operator.

It meters flower into the drum in adjustable pulses.

That maintains a more consistent working load and avoids dumping large quantities of flower into the drum at once.

Instead of increasing drum volume and then trying to control a large mass of flower inside it, we found it more effective to accurately control the amount entering a smaller cutting system.

That was a much simpler way to maintain consistent trimming conditions.

Far Fewer Wear Components

Large multi-reel systems also carried a significant component penalty.

Every additional cutting reel required another precision reel, blade location, drive system, bearings, adjustment points and supporting hardware.

Those are not inexpensive components.

A single-reel Master system eliminates most of that duplication.

Fewer wear components means:

• Lower replacement cost
• Less inventory of spare parts
• Fewer adjustment points
• Fewer potential mechanical failures
• Simpler maintenance
• Less specialized knowledge required from operators

Increasing production by adding complete simple systems proved more practical than concentrating many cutting mechanisms into one complicated machine.

Cleaning Became Dramatically Easier

Sanitation was another major difference.

We devoted considerable engineering to making the XL cleanable.

It included a removable cutting module, plumbing, spray systems and high-temperature Clean-in-Place equipment.

Those systems helped, but they were necessary largely because the machine itself had become difficult to access.

The Master took the opposite approach.

Its construction is open.

The drum is small.

The single cutting reel is easily accessible.

The surfaces that need inspection and cleaning are visible and reachable.

A thorough cleanup can therefore be performed extremely quickly without requiring an elaborate automated cleaning system.

For a commercial operator, faster cleaning means more than convenience.

It means shorter production interruptions and greater confidence that the machine has actually been inspected and cleaned thoroughly.

Less Electronic Complexity

The same principle applied to controls.

The XL required sophisticated electronics because there were many systems to coordinate.

That gave us valuable experimental capability, but it also created complexity.

The Master requires far fewer controls because the machine itself is fundamentally simpler.

Fewer electronic systems mean fewer components vulnerable to moisture, vibration, operator error or electrical failure.

They also make troubleshooting considerably easier.

Easier to Train Operators

A commercial machine should not require an engineer to keep it operating properly.

The large systems required considerably more understanding of interacting settings and components.

The Master was deliberately taken in the opposite direction.

The operator has fewer variables to manage, fewer systems to monitor and fewer maintenance procedures to learn.

That makes training easier and reduces dependence on highly experienced personnel.

For a growing operation with changing staff, that simplicity has real economic value.

What the Large-Drum Program Ultimately Taught Us

Our large machines were valuable because they answered questions we could not have answered from theory.

We learned that greater drum diameter could create more cutting area, but also changed flower movement.

We learned that multiple cutting reels did not automatically produce proportional throughput.

We learned that sophisticated controls could manage a complex machine, but those controls also became part of its complexity.

We learned that elaborate cleaning systems could make a large machine serviceable, but a fundamentally open and accessible machine was easier to clean in the first place.

Most importantly, we learned that commercial production capacity does not have to come from one enormous machine.

For a growing operation, multiple Master systems offered a better overall combination of:

• Gentler flower handling
• Better finished trim characteristics
• Higher finished-flower yield relative to trim
• Less hand touch-up
• Accurate automatic feeding
• Smaller equipment footprint
• Faster and more thorough cleaning
• Fewer wear components
• Simpler electronics
• Easier operator training
• Lower maintenance complexity
• Production redundancy
• Incremental capital investment

That was the real conclusion of the large-drum development program.

Instead of making one trimming machine larger and more complicated, we found it made more sense to keep the trimming process simple, controlled and gentle—and add another complete system when additional production was needed.

That is why Shearline returned to the 6.5-inch drum.

It was not a retreat from the larger machines we had built.

It was the result of what those machines taught us.