Designing a packaging line for both aluminum cans and glass bottles is not simply a matter of connecting two container formats to the same equipment.

The more important questions are:

Which equipment should remain dedicated? Which equipment can reasonably be shared? And how should the shared section be engineered to handle the very different characteristics of glass bottles and aluminum cans?

For many projects, a practical configuration is to keep the can filling/seaming system and glass bottle filling/capping system independent, while sharing selected downstream equipment such as conveyors, inspection systems, pasteurization, and secondary packaging.

This approach can reduce duplicated equipment and floor-space requirements without forcing fundamentally different filling processes into one machine.

But it also introduces a new engineering challenge:

Every shared section has to work for both container types—and the transition between them has to be controlled.

Based on our experience working through these projects, here are the areas we believe should be reviewed before designing a shared can-and-bottle packaging line.

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1. Start by Deciding What Should Be Dedicated and What Can Be Shared

The first design decision should not be:

“How much equipment can we share?”

A better question is:

“Which equipment makes operational sense to share?”

For a combination line, Redwood typically evaluates the system in three groups.

Dedicated Equipment

The primary filling and closure equipment will often remain container-specific:

Can Line

Can Filler → Seamer

Glass Bottle Line

Bottle Filler → Capper

Keeping these systems independent allows each filling process to be configured around the requirements of its container and product.

Shared Equipment

Depending on the project, selected downstream equipment may potentially serve both lines:

• Conveyors
• Accumulation
• Inspection systems
• Reject stations
• Pasteurization
• Date coding
• Labeling, where compatible
• Secondary packaging
• Case handling
• Palletizing

Whether an individual machine can actually be shared depends on the container formats, production rates, product requirements, equipment design, and required changeover process.

https://redwoodstainless.com/collections/canning-line

The objective is not to make every machine universal.

The objective is to find the right balance between capital investment, floor space, operating simplicity, and reliable production.

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2. Engineer the Merge Point Before Engineering the Rest of the Shared Line

When two dedicated packaging systems feed one downstream line, the merge point becomes one of the most important parts of the system.

Only one container stream should enter the shared downstream section at a time.

A typical arrangement may use pneumatic gates, isolation stops, controls logic, and physical separation to manage the transition.

The system should prevent a situation where cans and bottles are accidentally released into the shared section simultaneously.

This requires more than an operator procedure.

The control strategy should consider:

• Line selection
• Gate position
• Equipment status
• Conveyor permissives
• Upstream/downstream communication
• Fault conditions
• Restart conditions

For critical switching points, mechanical separation and electrical/control interlocks can provide additional protection against an unintended dual-line release.

A shared downstream line should have a clearly defined production path before either filler begins sending containers into it.

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3. The Conveyor Must Handle Two Very Different Containers

Glass bottles and aluminum cans behave differently on a conveyor.

Glass is relatively rigid and heavy, but it can break when containers collide, fall, or accumulate improperly.

Aluminum cans are much lighter and more susceptible to denting, scratching, tipping, compression, and unstable accumulation.

That means the same conveyor cannot necessarily use the same operating parameters for both.

For Glass Bottles

The conveyor strategy may need to emphasize:

• Stable container movement
• Controlled acceleration and deceleration
• Reduced impact between containers
• Appropriate guide-rail support
• Breakage management
• Controlled accumulation

For Aluminum Cans

The emphasis may shift toward:

• Flexible guide-rail adjustment
• Controlled back pressure
• Proper can spacing
• Reduced hard contact
• Prevention of can deformation
• Prevention of stacking or jamming

For a shared line, adjustable stainless steel guide rails and container-specific settings can help the same conveyor accommodate both formats.

The conveyor speed also needs to match the output behavior of each dedicated filling system.

Otherwise, a line that appears balanced at rated speed can still experience starvation, excessive accumulation, or repeated stops during actual production.

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4. Shared Inspection and Reject Systems Need Container-Specific Settings

A reject station designed around an aluminum can should not automatically be assumed to work the same way with a glass bottle.

The physical response of the containers is different.

A glass bottle may require a controlled reject action that minimizes impact and breakage.

An aluminum can may require lower-force handling to avoid denting or deforming the container.

The same principle applies to inspection equipment.

When changing formats, the line may need different recipes or settings for:

• Container detection
• Fill-level inspection
• Reject timing
• Reject force
• Container spacing
• Sensor position
• Fault handling

This is one reason changeover should be treated as a system procedure, not simply a mechanical adjustment.

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5. Shared Pasteurization Requires More Than a Format Change

If a tunnel pasteurizer or other thermal-processing equipment is shared, the operating recipe must be reviewed for each approved container and product combination.

Glass bottles and aluminum cans do not respond identically to temperature and pressure changes.

Depending on the process, engineering review may include:

• Product temperature
• Container temperature
• Heating profile
• Cooling profile
• Internal pressure
• Conveyor speed
• Residence time
• Container stability

The required process should therefore be established for the actual product and package combination rather than assuming that one thermal recipe can simply be reused.

Shared equipment does not necessarily mean shared process parameters.

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6. Changeover Is a Sanitation Event, Not Just a Mechanical Event

One of the most important lessons in a combination line is that changing from bottles to cans—or cans to bottles—is not only about guide rails and machine settings.

The shared production area also needs to be cleared and inspected.

After glass-bottle production, particular attention should be given to potential glass fragments in:

• Conveyor surfaces
• Guide rails
• Transfer points
• Drainage areas
• Equipment gaps
• Accumulation sections
• Reject stations

Before can production begins, the shared section should be inspected and cleared according to the facility's approved sanitation and foreign-material-control procedures.

Likewise, rejected cans, metal debris, closures, packaging materials, and previous-production remnants should be removed before the next production run.

Where product-contact systems are shared, cleaning procedures should be validated for the products and equipment involved.

A reliable changeover should reset both the equipment and the production environment.

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7. Keep Container-Specific Materials and Change Parts Separate

Shared equipment does not mean every component should be shared.

Can ends, bottle closures, change parts, wear components, guides, blocks, and other format-specific items should be clearly identified and controlled.

A good changeover procedure should include:

CLEAR → CLEAN → CHANGE → SET → VERIFY

Clear

Remove remaining containers, closures, packaging materials, and work-in-process from the previous run.

Clean

Clean and inspect the shared production area according to the approved sanitation and foreign-material-control procedure.

Change

Install the correct container-specific change parts.

Set

Load or adjust the correct operating recipe, guide positions, conveyor settings, inspection parameters, and downstream equipment settings.

Verify

Run and inspect first articles before releasing the line for normal production.

This simple sequence can become the foundation of a repeatable changeover checklist.

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8. Material Selection Matters More on a Shared Line

A shared conveyor has to operate under the requirements of both production modes.

For combination glass-bottle and can projects, Redwood evaluates stainless steel conveyor construction because the shared equipment may be exposed to glass fragments, repeated sanitation, moisture, container impact, and different loading conditions.

The exact conveyor construction should be selected for the application, but the design review should consider:

• Cleanability
• Corrosion resistance
• Wear resistance
• Container stability
• Foreign-material control
• Maintenance access
• Drainage
• Guide-rail adjustment
• Resistance to damage from broken containers

The important point is not simply specifying a material.

It is understanding how the conveyor will behave after thousands of transitions between two different container types.

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9. Build Jam Detection and Recovery Into the Shared Section

The shared section should also be evaluated for what happens when production does not run perfectly.

Glass bottles can accumulate and break.

Cans can tip, stack, deform, or jam.

Sensors and controls can therefore be used to identify abnormal accumulation and coordinate equipment response.

Depending on the system design, this may include:

• Photoelectric jam detection
• Accumulation monitoring
• Conveyor speed coordination
• Automatic stop logic
• Controlled restart sequences
• Upstream/downstream interlocks

The question is not only:

“Can the line run?”

It is also:

“What happens when one part of the line stops?”

That recovery behavior can have a significant effect on usable production output.

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10. Safety Requirements Change With the Container

Glass introduces risks that do not exist in the same way with aluminum cans.

Glass-production areas may require additional guarding, fragment containment, collection points, and cleaning procedures.

Before switching back to cans, the shared equipment should be inspected for remaining glass fragments.

The two dedicated filler discharge paths should also be protected against unintended simultaneous operation through the approved control and isolation strategy.

Closure equipment remains container-specific as well. Seamer and bottle-capper settings should follow the approved equipment and package requirements rather than being treated as interchangeable settings within the shared downstream system.

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11. Maintenance Should Follow the Production Mode

A combination line also changes how maintenance teams should think about inspection.

After extended glass-bottle production, attention may be directed toward areas such as:

• Conveyor wear
• Guide-rail condition
• Impact points
• Reject mechanisms
• Evidence of glass accumulation or damage

After can production, inspection priorities may include:

• Flexible guides
• Can-contact surfaces
• Container compression points
• Change parts
• Wear associated with the approved can-handling system

Container-specific spare and wear parts should also be identified and stored separately where appropriate.

This makes changeover easier and reduces the possibility of installing the wrong component during maintenance.

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The Real Engineering Question: What Should You Share?

A combination can-and-bottle line can make sense when a producer wants to support multiple package formats without duplicating every downstream machine.

But maximum equipment sharing should not be the goal.

Sometimes sharing a conveyor makes sense.

Sometimes sharing inspection equipment makes sense.

Sometimes a pasteurizer, case packer, or palletizing system can support both production paths.

And sometimes adding another dedicated machine makes the overall system simpler to operate.

That decision should be made by looking at:

Production Volume → Container Formats → Changeover Frequency → Floor Space → Labor → Sanitation → Process Requirements → Future Growth

The result may look something like this:

CAN: Filler + Seamer
↓
Controlled Merge
↓
Shared Conveying → Inspection → Pasteurization → Packaging → Palletizing
↑
BOTTLE: Filler + Capper

The engineering work happens at the boundaries.

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Plan the Shared Line Before You Buy the Machines

If you are considering both glass bottles and aluminum cans, start by mapping the complete production path rather than evaluating each machine independently.

Identify:

• Which equipment should remain dedicated
• Which equipment may be shared
• Where the two production paths merge
• What needs to change between formats
• Which operating parameters require separate recipes
• How sanitation and foreign-material control will be handled
• How containers will accumulate and recover after a stop
• Who owns each changeover and verification step

Redwood Stainless Systems can review the production requirements, container formats, expected output, facility layout, and downstream packaging needs to help develop an appropriate system configuration.

Planning a combination can-and-bottle packaging line?

Request a Technical Scope Review →

Final equipment configuration, operating parameters, sanitation requirements, utility requirements, and performance criteria should be established from the approved project specifications and process requirements.