Table of Contents
- Cutting Danpla Sheet: Methods and Tools
- Heat Bending Danpla: The Core Technique
- Heat Bending Parameters by Sheet Thickness
- Equipment Required for Heat Bending
- Scoring Before Folding
- Bonding, Welding and Joining Danpla Sheet
- Related Articles
- Frequently Asked Questions about Danpla Fabrication
- Contact ICD Vietnam
Reviewed and updated by ICD - Week 30/2026
Danpla PP (hollow-core polypropylene) can be fabricated by several methods: cutting with a knife or saw, heat bending, scoring, heat welding, and UV printing. This guide covers heat bending in detail - the most common technique for forming danpla boxes and trays - along with the other essential fabrication methods you need to know.
Cutting Danpla Sheet: Methods and Tools
Danpla cuts more easily than wood or solid plastic because the hollow-core structure creates less friction. Choose the method based on thickness and volume:
| Method | Best for | Notes |
|---|---|---|
| Sharp utility knife (Stanley, Olfa) | 2-3 mm sheet, small quantities | Use a metal ruler; score 2-3 passes rather than one single cut |
| Circular saw with fine-tooth TCT blade | 3-6 mm sheet, straight cuts in volume | High speed, 80-100 tooth blade to avoid melting the PP |
| CNC router | Shaped cuts, large volumes | Spindle speed 8,000-12,000 RPM; do not exceed 18,000 RPM |
| CO2 laser cutter | Small details, lettering, logos | PP melts rather than burns - good ventilation required, use high travel speed |
| Hot knife | Straight cuts, edge sealing | Temperature 200-230 deg C; move slowly for a clean melt |
Important note: Cutting across the flutes (perpendicular to the channels) is easier and gives a cleaner edge. Cutting parallel to the flutes lets the blade drift into a channel - press more firmly and cut more slowly.
Heat Bending Danpla: The Core Technique
Heat bending creates a hard fold line (90 degrees or any desired angle) in a danpla sheet without cutting it apart. The result is a single-piece finished part with no joints - stronger and neater than assembling separate panels with adhesive or tape.
Principle: PP becomes pliable at 160-180 deg C (the bending temperature) and can be formed into any shape, holding that shape once cooled. At 160 deg C the hollow cores soften enough to bend without cracking. Above 190 deg C, PP begins to flow and deforms uncontrollably.
Heat Bending Parameters by Sheet Thickness
| Thickness | Bending temperature | Minimum bend radius | Heating time |
|---|---|---|---|
| 2 mm | 160-170 deg C | 4 mm | 30-45 seconds |
| 3 mm | 165-175 deg C | 6 mm | 45-60 seconds |
| 4 mm | 170-180 deg C | 8 mm | 60-90 seconds |
| 5 mm | 175-185 deg C | 10 mm | 90-120 seconds |
| 6 mm | 180-190 deg C | 12 mm | 120-150 seconds |
Minimum bend radius rule: The practical rule is minimum bend radius = 2 x sheet thickness. Bending tighter than this cracks the outer face or collapses the hollow cores. For a standard danpla box with a 90-degree corner, a bend radius of 8-10 mm on 4 mm sheet is the most common ratio.
Equipment Required for Heat Bending
Strip heater: The dedicated tool - a flat resistance heating element with adjustable temperature from 100 to 300 deg C. Place the danpla sheet on the strip at the intended fold line, wait the required time, then bend to the required angle. This is the correct method for production runs. Strip heater price: 3-8 million VND depending on bar length.
Heat gun: More flexible but harder to apply heat evenly. Use for curved bends or irregular shapes. Hold the nozzle 3-5 cm from the sheet and move steadily along the fold line. Holding in one spot causes localised melting. Industrial heat gun price: Liên hệ báo giá.
Flat electric hotplate: The simplest manual method. Place a straight metal bar on the hotplate at medium heat (around 180 deg C), then rest the danpla sheet on the hot metal bar at the intended fold line. Suitable only for small quantities where precision is not critical.
Forming jig: Always use a wood or metal jig to hold the correct angle while the sheet cools. Do not hold by hand - PP contracts as it cools and the angle will spring open by 2-5 degrees. A simple jig can be a square timber block and a few G-clamps.
Scoring Before Folding
As an alternative to heat bending, scoring uses a knife or CNC cutter to cut halfway into the sheet thickness at the intended fold line. The sheet then folds along the scored line without heat.
Advantages of scoring: Faster than heat bending, no heating equipment needed, suitable for complex designs with many fold lines. Disadvantages: The fold is less durable and may crack over time if the sheet is repeatedly flexed. Not suitable for boxes carrying heavy loads.
Scoring rule: cut to 40-50% of sheet thickness; cutting beyond 60% weakens the sheet excessively. Score on the outer face (opposite to the direction of fold) for a more accurate bend.
Bonding, Welding and Joining Danpla Sheet
Adhesive: PP is difficult to bond (low surface energy). Use two-part epoxy, cyanoacrylate super glue formulated for PP, or pre-treat the surface with a flame or plasma before applying standard adhesive. Ordinary double-sided tape does not bond to PP.
Heat welding: The most durable method. Use a plastic welding gun or ultrasonic welder to fuse two danpla edges together. A heat-welded joint is stronger than adhesive and more water-resistant. Suitable for producing boxes in volume.
Nylon rivets and bolts: Mechanical fastening for boxes that need to be disassembled. Drill a 4-6 mm hole and use plastic rivets or M4-M6 nylon bolts. Avoid metal rivets on ESD danpla - they create uncontrolled conductive points.
Related Articles
| What is danpla? Structure, specs and types | Standard danpla sheet sizes for fabrication | Buy danpla sheet from ICD Vietnam |
Frequently Asked Questions about Danpla Fabrication
1. Can ESD danpla be heat bent?
Yes. ESD danpla is heat bent using the same parameters as standard PP danpla (160-180 deg C). The carbon black in ESD danpla does not affect heat-bending performance. However, temperatures above 190 deg C can alter the carbon distribution and affect electrical resistance - stay toward the lower end of the recommended range.
2. Will the bend angle spring back after heat bending?
PP has a spring-back effect of around 2-5 degrees after cooling. To compensate, overbend by 3-5 degrees beyond the target angle and hold in the jig until fully cooled (5-10 minutes). Do not remove the jig while the sheet is still warm.
3. Can 4 mm danpla be bent to 180 degrees?
Technically possible if you bend slowly with sufficient heat, but the outer face will be under tension and may develop micro-cracks. Bending beyond 120 degrees is not recommended for 4 mm sheet. If a 180-degree fold is needed, scoring and folding is a better option.
4. Does ICD Vietnam fabricate custom danpla boxes from drawings?
Yes. ICD Vietnam fabricates danpla boxes, trays, and dividers to technical drawings (DWG, PDF) or physical samples. Sample lead time is 3-5 days; production runs take 7-15 days depending on quantity and complexity.
Contact ICD Vietnam
Hotline: 0983 797 186 / 090 345 9186 / 090 5859 186
Email: sales@icdvietnam.com.vn | Zalo: Chat Zalo
