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Contents▪ Overview of Candle Packaging
▪ The Thermoforming Process and More
▪ Overview
▪ Vacuum Forming, Pressure Forming, Drape Forming
▪ Prototype Process Options
▪ Tooling Process
▪ Production Equipment Set-up
▪ What is Thermoforming?
▪ Inspection Considerations
▪ Process for Customization Options
▪ Packaging Material Options
▪ Comparative Applications for PET and PVC Candle Packaging
▪ Limitations of Packaging Materials
▪ Fragrance & Essential Oil Compatibility
▪ Summary
Overview of Candle Packaging
▪Candle packaging is manufactured using the thermoforming process with PVC, PET and other thermoplastic materials as required.
▪ This presentation will explain the different types of thermoforming processes, tooling, machine set-up, inspection considerations, customization options, uses and limitations of PET and PVC materials for candle applications fragrance compatibility.
Typical Thermoformed Products for the Candle Industry
▪ A Wide Variety of Single and Multi-Cavity Packaging Products can be manufactured using the Thermoforming Process
▪ Some Examples are:
6 Cavity Melt Clamshell P.O.P. Display Tray
Vacuum Forming▪ In Vacuum Thermoforming,
vacuum is used to pull the hot film/sheet of plastic against the mold
▪ Used to obtain a more defined part/component by way of applying vacuum to the film/sheet
▪ Some formers utilize both vacuum and pressure to increase definition of part/component providing for the best possible outcome
▪ Due to the mold complexity, tooling is slightly more costly than the Drape Formed version.
Pressure Forming
▪ In Pressure Thermoforming, pressure is used to push the hot plastic film or sheet against the mold
▪ Used to obtain a more defined part/component by way of applying pressure to the film/sheet
▪ Also aides in the cooling process
▪ Some formers utilize both pressure and vacuum to increase definition of part/component providing for the best possible outcome
▪ Due to the mold complexity, tooling is slightly more costly than the Drape Formed version.
Drape Forming
▪ In Drape Forming, no vacuum is used
▪ Used for parts with a more gradual bends and little to no definition
▪ Tooling costs are less than Vacuum and/or Pressure Formed versions
▪ Typically not used for production quantities
Drape Forming
Prototype Process for Composite Tooling▪ Engineering creates 2D drawing to determine layout (tool size, machine
utilization, type of material, blank material size, cycle times for equipment, secondary operations and more)
▪ Engineering creates geometry for Pattern Shop to produce
composite tool
▪ Programming takes above geometry & creates geometry for
prototype cutting die(s)
▪ Pattern Shop manufactures composite (typically R-Shape or
Repro) prototype tool
▪ Tool Shop mounts composite tool onto a base plate & box for prototyping process
▪ Die Shop cuts, bends, lines & mounts steel-rule die for prototype die-cutting process
Prototype Process for 3D Printed Tooling
▪ Engineering creates 2D drawing to determine layout (tool size, machine utilization, type of material, blank material size, cycle times for equipment, secondary operations and more)
▪ Engineering creates geometry for 3D Printer & uploads STL file to
produce composite tool
▪ Material is then loaded into the 3D Printer & print program is run
▪ Programming takes above geometry & creates geometry for
prototype cutting die(s)
▪ Tool Shop mounts 3D Printed tool onto a base plate & box for prototyping process
▪ Die Shop cuts, bends, lines & mounts steel-rule die for prototype die-cutting process
Production Tooling Process
▪ Engineering creates 2D drawing to determine layout (tool size, machine utilization, type of material, blank material size, cycle times for equipment, secondary operations and more)
▪ Engineering creates geometry CNC Machining Center cutter paths
▪ Programming takes above geometry & creates CNC Machining
Center programs & geometry for cutting die(s)
▪ Machining Center manufactures 1st Tool Profile for customer approval
▪ After customer approval, Machining Center manufactures remaining
▪ Die Shop cuts, bends, lines & mounts steel-rule die for die-cutting process
Production Equipment Set-Up
1. Install forming station – used to form part
2. Set-up & mount pressure box (if applicable) – used to provide for more definition of part/component
3. Set-up & mount plug assist (if applicable) – used to assist heated material further down into the cavities
4. Install Trim Station (if applicable) – used to die-cut parts/components
5. Install & Align Stacker Station (if applicable) – used to separate & stack parts/components
6. Trouble shoot set-up & make adjustments as needed to all of the above
7. Submit full shot (cut & uncut) to Quality Control (if applicable) for inspection
Basic Thermoforming StepsStep 1: Material enters oven
Heating the plastic film or sheet to a softening temperature
Step 2: Material comes out of the oven and proceeds to the Forming Station
Parts/components are formed over the mold
Step 3: Parts then proceed from the forming
station to the Die Station (if applicable)
Parts/components are die-cut by way of a
floating steel-rule die(s)
Step 4: Parts/components then proceed to the Stacker Station where they are separated and stacked (if applicable)
Step 5: Final Inspection of parts/components (if applicable)
Process Inspection▪ All products should be subject to manual in-process inspections
▪ Inspection process should be performed
▪ at the beginning of production
▪ once per hour, at a minimum
▪ at least one carton per skid before shipment
▪ Typical inspection steps includes
▪ visual for proper forming and color consistency
▪ dimensional inspection
▪ clamshell functionality – do they stay closed when snapped together?
▪ visual/manual for hanger holes proper cut and ease of removal
▪ liquid leak check using hot (150F) water
Causes for Inspection Failure
▪ Webbing (wrinkling in the part)
Lack of vacuum holes
Sheet material inconsistent
▪ Poor product detail
Insufficient vacuum, vacuum leaks
Sheet too cold
▪ Blisters or bubbles
Moisture in the sheet
Causes for Inspection Failure
▪ Product that is cut out of tolerance or is not clean / Hanger holes that cannot be easily removed
Dies require new cutting rule
New die plate needed
▪ Product that is difficult to close or does not remain closed
Cold forming (sheet too cold)
▪ Products that leak during the hot water check
Defects in film – blemish, pin holes, debris
Something on mold or plug
Process Customization Options
▪ Customized Products can Include
▪ Candle Covers (round or square, male or female), Blisters, Clamshells, Tri-folds, Display Trays, Molds, Box Inserts, and more
▪ Wick holes (punched or punched and cleared)
▪ Custom cut-outs to the customers specifications
▪ Logos and/or patterns using hot stamped colored foil or printed labels
▪ Logos and/or patterns engraved into the tooling (size of area to be engraved will contribute to the legibility of the engraved logo and/or pattern)
▪ Materials in custom colors, grades and gauges
▪ As expected, customized products do come at a higher cost
Design Related Tooling Options
▪ Custom Designs can be incorporated into the final part by machining patterns into the tooling. When the plastic hardens, it takes the shape of the designs.
• Tooling and process cost must be considered when incorporating custom patterns
• Standard non-custom tooling will always be lower cost• Custom shapes requiring definition typically require vacuum
and/or pressure forming
Packaging OptionsClear PVC Clear PET
Max Use Temperature (0F) 155 145
Price Comparison Blue Tint - Lowest
Water Clear - Higher
Higher (typically)
Typical Grades General Purpose APET (Virgin)
RPET (Recycled or Utility)
Typical Clarity Blue Tint & Water Clear APET – Clear
RPET – Clear to Off Color Clear
Recycle Codes 3 1
Waxes Availability
Soy marginal Yes
Paraffin Yes Yes
Blended Wax Yes Yes
Palm Wax Yes No
PVC is the preferred material because of low cost, higher impact and cold crack resistance unless there are compatibility issues with the fragrance and essential oil additives
Limitations of Packaging Materials
▪ Packaging Materials Should be Stored under Controlled Temperature and Environmental Conditions
▪ Exposure to freezing temperatures or temperatures above 90F can reduce the shelf life of the material.
▪ Exposure to sunlight and humidity swings can also reduce shelf life
▪ A typical acceptable shelf life is six months.
▪ Long term storage at room temperature in airtight sealed and dark containers may help extend the shelf life.
▪ Any exposure to temperature, sunlight and humidity can
▪ Cause discoloration
▪ Reduce flexibility (cause brittleness)
▪ Reduce chemical resistance
▪ Reduce thermal performance
Fragrance and Essential Oil Compatibility(reference Hansen solubility parameters)
▪ Fragrances and Essential Oils are additives in many candle waxes
▪ These additives can be absorbed into the packaging and act as ‘plasticizers’
▪ A plasticizer will soften the plastic and reduce its use for the application
▪ Reference: The American Institute for Conservation site that discusses solubility parameters with a section on Hansen.
http://cool.conservationus.org/coolaic/sg/bpg/annual/v03/bp03-04.html
▪ In order to determine the correct packaging material up front, the wax formulation and solubility parameters of the packaging must be known. If unknown, testing is highly recommended.
▪ For example…
▪ Essential oils are caustic to PET at 10% loading, but ok at 3% or less
SUMMARY
▪ The thermoforming process is a low cost method to manufacture quality candle packaging products using clear PVC and PET polymers
▪ Customized patterns, shapes and multiple cavities are just some of the options that can be incorporated into the thermoforming process
▪ Proper selection of the plastic will ensure compatibility with the wax and additives
▪ Materials, number of tool cavities, design options will all contribute to the final product cost
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