This guide is designed to help you select custom corrugated plastic sheets that meet the specific needs of your application. You’ll learn everything there is to know about corrugated plastic sheets and receive a handy checklist to help you prepare for bulk orders.
Start With the Application, Not the Sheet Specification
Start by defining the intended use and requirements of your custom corrugated plastic sheets. Share the working conditions and expected service life with your supplier to help determine suitable specifications.
For a yard sign, explain how it will be printed and installed, and how long it needs to stay outdoors. These details help you confirm:
- Printing surface: Confirm whether corona treatment is needed for your ink and printing process to improve surface wetting and support ink adhesion.
- Printing method: Specify whether you will use UV digital, screen, or Flexographic printing.
- Outdoor requirements: For long-term outdoor use, confirm whether the sheets need UV stabilizers based on local sunlight exposure and the intended service life.
Recommended Reading: Choose Corrugated Plastic By Industry
Choose the Right Thickness and GSM
Two corrugated plastic sheets can have the same thickness but different weights per square meter. To understand the difference, you need to look at both the sheet’s overall depth and its hollow structure.
What Do Thickness and GSM Measure?
- Thickness, measured in millimeters, is the distance between the sheet’s top and bottom surfaces. It includes the hollow space inside.
- GSM means grams per square meter. A sheet rated at 600 GSM weighs 600 grams for each square meter of material.
These measurements describe different features of the sheet.
Why Can the Same Thickness Have Different GSM?
Corrugated plastic sheets have two outer faces connected by internal ribs. The ribs form hollow channels between the faces. See Coroplast’s technical description.
This structure allows different amounts of material within the same overall thickness. With the same material formulation, GSM can vary through:
- Outer face thickness: Thicker top and bottom faces contain more material.
- Internal rib thickness: Thicker ribs add material inside the sheet.
- Rib spacing: More closely spaced ribs add material when other dimensions remain unchanged.
The overall sheet can still measure 4 mm, even when the amount of material in its faces and ribs changes.
A Simple Example
Consider two sheets with the following specifications:
These values illustrate the difference between thickness and GSM.
Sheet B weighs 200 grams more per square meter, despite having the same overall thickness. If both use the same material formulation, that extra weight represents more material within the sheet’s structure.
Manufacturer data also demonstrates this distinction: Coroplast lists several material weights at a 4 mm thickness. See Coroplast packaging specifications.
When requesting a quote, specify both thickness and GSM, along with the acceptable variation for each. Compare material formulation and performance requirements alongside these numbers.
Confirm Printing and Surface Treatment Requirements
Tell your supplier whether the sheets will be printed, who will print them, and which process will be used. These details help define the surface treatment and sample checks before production.
Do You Need Printing?
Confirm whether the finished product needs logos, instructions, barcodes, or display graphics.
If the sheets will remain unprinted, state this clearly. Mention any planned adhesive labels or bonding, as these may also require surface preparation.
Blank Sheets vs. Finished Printed Sheets
- Blank sheets: You receive unprinted material for further processing. If your team or a local printer will print it later, confirm the printing requirements before ordering.
- Finished printed sheets: The supplier prints your approved artwork. Confirm the printed sides, colors, design placement, and sample approval process.
Blank sheets can still be corona treated. “Blank” describes the absence of printing; it does not specify the surface treatment.
Choose the Printing Method
Use the following comparison as a starting point for discussion with your supplier:
Digital printing avoids printing plates, which makes design changes easier. Flexographic printing involves image carriers and setup costs that should be included in the quotation. See Mimaki’s digital printing explanation, Luminite’s flexographic printing guide.
Confirm that the selected press and ink system are suitable for corrugated polypropylene sheets.
What Does Corona Treatment Do?
Corona treatment uses an electrical discharge to increase the plastic’s surface energy. This helps compatible inks spread across the surface and adhere. See Enercon’s technical overview.
Before ordering, agree on:
- Treated sides: One side or both sides.
- Treatment target: The surface wetting level required by your printer or ink supplier, commonly expressed as a dyne level.
- Printing schedule: When printing will take place after production, shipping, and storage.
Treatment levels can decrease over time. A dyne reading also needs to be supported by an adhesion test with the intended ink. See Enercon’s guidance on dyne levels and adhesion.
Recommended Reading: Why is corona treatment necessary?
Why Must Buyers Confirm the Printing Method Before Ordering?
Different ink systems have different surface requirements. Your supplier needs the final printing method to assess treatment, sheet suitability, and any additional preparation.
For example, if a local printer will use UV digital printing, share the printer model and ink series before ordering blank sheets. Ask the printer to test a sample using the intended production settings.
Ink manufacturers may specify both surface treatment requirements and additional adhesion promoters. Fujifilm’s Uvijet KL technical sheet, for example, recommends substrate testing before a commercial run.
Understand Water, Chemical and Outdoor Performance
Describe the conditions your custom corrugated plastic sheets will face. Water contact, cleaning routines, chemicals, and sunlight each affect the specification.
Water Resistance
Corrugated polypropylene sheets have low water absorption.
Water can still enter through open flutes or unsealed joints. If the finished product must keep contents dry, discuss edge sealing and joint design with your supplier.
Washability
Specify the cleaning method, water temperature, cleaning products, and wash frequency. These details help your supplier assess suitability for repeated cleaning.
Test a finished sample through the intended wash cycles. Include printed surfaces, joints, and any liners in the check. Confirm how the product will drain and dry.
Chemical Exposure
Chemical compatibility depends on the chemical type, concentration, temperature, and contact time. ASTM D543 provides practices for evaluating plastics under defined chemical exposure conditions. See ASTM D543-21.
Share the actual chemicals the sheets will contact. Ask your supplier to confirm compatibility with the proposed material grade and any printing or coatings.
UV Exposure
Prolonged UV exposure can cause cracking and loss of strength. UV stabilizers help reduce this damage. See BASF’s light stabilizer guidance.
For outdoor use, share the installation location and expected service life. Confirm whether the proposed grade includes UV stabilization, and request evidence supporting its outdoor performance.
Check printed graphics separately, as their outdoor durability also depends on the ink and printing system.
Check Fire-Retardant Requirements Before Ordering
Standard grades are intended for general use. Fire-retardant (FR) grades use formulations designed to improve fire performance under specified test conditions.
Fire-retardant does not mean fireproof.
Confirm the Project Requirement
Ask the project team to identify the required test standard and classification. Include both in your inquiry.
The standard must suit the intended application. For example, a UL 94 rating does not replace the fire tests required for building applications. See UL Solutions’ guidance.
Check the Supporting Report
Request the complete report from a third-party laboratory. Review these details:
- Laboratory: Confirm that its accreditation covers the relevant test. See ILAC’s accreditation guidance.
- Report number: Record the number and issue date. Verify the document with the issuing laboratory.
- Tested specification: Compare the tested thickness, GSM, and product configuration with your order. Check the material formulation, printing, coatings, and mounting conditions where relevant.
A test report does not automatically cover every custom specification.
If your order differs from the tested product, ask the laboratory to confirm whether the documented scope covers those differences. Further assessment or testing may be needed. See Warringtonfire’s guidance on product variations.
Recommended Reading: Flame-Retardant Corrugated Plastic Sheets: 6 Essential Things to Know
Specify Sheet Size, Flute Direction, Color and Fabrication
Turn your requirements into a purchase specification sheet. Include the details below alongside your agreed thickness, GSM, and material grade.
Flute direction also affects cutting and creasing setup. Coroplast’s conversion guidance describes different processing considerations along and across the flutes. See Coroplast’s technical guidance.
Use the same approved drawing revision for the quotation, sample, and production order.
Understand MOQ and Lead Time for Custom Production
MOQ means minimum order quantity. For custom corrugated plastic sheets, it depends on the materials and production setup needed for your order.
Why Can Custom Requirements Affect MOQ?
- Custom color: Color compounds may have their own purchasing minimums. Switching colors can also require equipment cleaning. See Omega Plastics’ color matching guidance.
- Custom formulation: Special resin or additive blends may require separate material orders and production batches.
- Custom specification: Thickness, GSM, and fabrication requirements can change machine setup and processing work.
These requirements can make small production runs less economical.
Ask whether MOQ applies per color or specification. Coroplast, for example, publishes minimums by thickness, color, and size. See Coroplast’s ordering specifications.
Custom Manufacturing vs. Stock Supply
A custom-only manufacturer without finished stock needs to arrange production for your order. Its MOQ reflects the batch needed to make your chosen specification.
A retailer or distributor holding stock can split an existing batch into smaller orders. Its minimum may depend on pack sizes and warehouse handling.
When Should Buyers Confirm Lead Time?
Request estimated sample and production lead times during quotation. Reconfirm the production schedule once the sample and final specifications are approved.
Plan around this sequence:
Sample → Approval → Mass production
- Sample: Agree on preparation and shipping time. Allow time for any required testing.
- Approval: Confirm the accepted sample, drawings, color, and artwork in writing. Include time for revisions in your plan.
- Mass production: Confirm the production slot and expected completion date. Agree on what starts the lead-time clock, including sample approval and any agreed deposit requirement.
Confirm whether the quoted lead time ends at production completion or dispatch. Plan transport time separately.
Plan Your Custom Sheet Order With Confidence
Choosing custom corrugated plastic sheets starts with understanding the job they need to do. Clear specifications, relevant test evidence, and an approved sample help you compare quotes and agree on what will be produced.
At JIANXIN PLASTIC, we can help turn your application needs into a proposed specification. Share a drawing, an existing sample, or a brief project description, and we can work through the remaining details together. Contact us!
