В Пластиковый прототип производство field, Стр (Полипропилен) blow molding prototype parts are highly favored in industries such as packaging, Автомобиль, and home appliances. This is thanks to PP’s excellent properties like light weight, Высокая ударная стойкость, and good chemical stability. Однако, processing PP blow molding prototypes is not without difficulties. Many manufacturers face problems such as poor parison stability, неровная толщина стенки, and insufficient prototype durability during production. This article will break down the entire processing process of PP blow molding prototype parts based on six core themes, providing practical solutions to common issues and helping you produce high-quality PP prototypes efficiently.
1. Выбор материала: The Cornerstone of High-Performance PP Prototypes
Выбор материала directly determines the basic performance and processing feasibility of PP blow molding prototype parts. Unlike PVC, PP has better thermal stability but is sensitive to external factors like temperature and additives during processing. Choosing the right PP material and matching additives is the first step to ensure prototype quality.
1.1 Key Factors in PP Material Selection
| Фактор | Подробности | Влияние на прототип |
| Полипропилен (Стр) Оценки | Homo-PP (Высокая жесткость, low impact resistance), Co-PP (random copolymer: Хорошая прозрачность; block copolymer: Высокая ударная стойкость) | Homo-PP is suitable for rigid prototypes like plastic crates; random Co-PP for transparent prototypes like food containers; block Co-PP for impact-resistant prototypes like automotive bumpers |
| Свойства материала | Плотность (0.90-0.91 G/CM³), Точка плавления (160-170℃), Предел прочности (30-40 МПА), Воздействие сила (2-10 KJ /) | Low density reduces prototype weight; high melting point ensures stability during high-temperature processing; excellent tensile/impact strength enhances prototype durability |
| Переработанные материалы | Content (0-50%): Low-content (＜20%) maintains performance; high-content (20-50%) reduces cost but lowers strength | For non-critical prototypes (НАПРИМЕР., ordinary packaging), 20-30% recycled materials can be used; Для высокопроизводительных прототипов (НАПРИМЕР., Автомобильные детали), использовать 100% virgin PP |
| Добавки | Антиоксиданты (prevents aging), УФ -стабилизаторы (resists sunlight damage), nucleating agents (improves crystallization), цветовые средства | Antioxidants extend prototype service life; UV stabilizers are essential for outdoor prototypes; nucleating agents enhance rigidity; colorants meet appearance requirements |
Общий вопрос здесь: Why do some PP prototypes become brittle after long-term use? The main reason is improper additive matching—either no antioxidants are added (leading to oxidation aging) or insufficient UV stabilizers are used (for outdoor prototypes). It is recommended to add 0.1-0.3% antioxidants (нравиться 1010) и 0.2-0.5% УФ -стабилизаторы (like UV531) for prototypes used outdoors or in harsh environments.
2. Фаза дизайна: Lay the Groundwork for Smooth Processing
А design phase is crucial for ensuring that PP blow molding prototype parts can be processed smoothly and meet functional requirements. 不合理的设计 often leads to processing defects like uneven wall thickness and difficult demolding.
2.1 Core Design Elements for PP Blow Molding Prototypes
| Дизайн элемент | Requirements | Обоснование | Практический пример |
| Моделирование CAD | Используйте программное обеспечение, такое как SolidWorks, Autocad; ensure 3D model accuracy (Допуск ± 0,05 мм) | Accurate modeling provides a reliable basis for mold making and processing | When designing a 500ml PP bottle prototype, the CAD model should clearly mark the bottle mouth diameter (28мм), высота (200мм), and bottom thickness (2мм) |
| Толщина стены | Равномерная толщина (variation ≤8%); minimum thickness ≥0.5mm (Для небольших прототипов), ≥1mm (for large prototypes) | Uneven thickness causes uneven cooling (leading to deformation); too thin thickness reduces strength | For a PP bucket prototype (diameter 300mm), design the wall thickness as 1.5±0.1mm; Избегайте внезапных изменений толщины (НАПРИМЕР., from 1mm to 3mm) |
| Part Geometry | Избегайте острых углов (radius ≥2mm); set reasonable draft angle (1-3° for vertical surfaces) | Sharp corners cause stress concentration (easy to crack); draft angle facilitates demolding (PP has high friction) | When designing a PP box prototype with a lid, set the draft angle of the box sidewall to 2°; round the corner between the sidewall and bottom to R3mm |
| Дизайн для производства (DFM) | Simplify complex structures; avoid undercuts (difficult to demold); reserve trimming allowance (0.5-1мм) | Reduces processing difficulty and cost; ensures smooth production | For a PP handle prototype integrated with a bucket, design the handle as a separate part (assembled later) instead of an integrated undercut structure |
2.2 Общие ошибки дизайна & Corrections
- Ошибка 1: No draft angle on vertical surfaces → Prototype sticks to the mold during demolding (легко поцарапать).
Коррекция: Add a 1.5° draft angle; apply a small amount of mold release agent (Силиконовая на основе) during processing.
- Ошибка 2: Too thin wall thickness (0.3mm for a small bottle prototype) → Prototype is easily crushed (предел прочности <25МПА).
Коррекция: Increase wall thickness to 0.6mm; add a nucleating agent (0.2%) to improve material strength.
3. Blow Molding Process: The Core of PP Prototype Shaping
А blow molding process is the key link that converts PP raw materials into prototype parts. Each step requires precise control—PP’s high melt viscosity and slow crystallization rate make process parameters critical to prototype quality.
3.1 Step-by-Step PP Blow Molding Process & Control Points
- Экструзия Парисона
Melt PP material (virgin + добавки) in the extruder (barrel temperature: Zone 1=140-150℃, Zone 2=150-160℃, Zone 3=160-170℃). Extrude into a tube-shaped parison at a speed of 10-20mm/s. The key is to ensure parison stability: use a parison controller to adjust the die gap (1-3мм) в реальном времени. Например, if the parison is too thick on the left side, reduce the left die gap by 0.1mm.
- Дизайн плесени & Зажим
The mold cavity surface should be polished (RA 0,8-1,6 мкм) to ensure smooth prototype surfaces. Clamp the parison with a force of 15-30kN (Небольшие прототипы: 15-20кН; large prototypes: 25-30кН). The clamping time should be 1-2 seconds—too fast causes parison deformation; too slow leads to material cooling (difficult to inflate).
- Blow Pressure & Инфляция
Inject compressed air into the parison at a pressure of 0.5-1.0MPa. For thin-walled prototypes (＜ 1 мм), use low pressure (0.5-0.7МПА) Чтобы не взрываться; for thick-walled prototypes (＞1.5mm), use high pressure (0.8-1.0МПА) Чтобы обеспечить полное расширение. Время инфляции 3-5 seconds—until the parison fully adheres to the mold cavity.
- Время охлаждения & Время цикла
Охладить прототип с водяным охлаждением (температура формы: 20-40℃). The cooling time is 5-15 секунды (thinner prototypes: 5-8с; thicker prototypes: 12-15с). PP’s slow crystallization requires sufficient cooling to prevent deformation. The total cycle time (extrusion → clamping → inflation → cooling → ejection) является 20-30 seconds for small prototypes and 30-50 seconds for large ones.
- Выброс
Open the mold and eject the prototype at a speed of 5-10mm/s. PP is hard when cold, so avoid fast ejection (prevents prototype damage). После выброса, Поместите прототип на охлаждающую стойку для 10-20 минуты (Охлаждение комнатной температуры) to stabilize dimensions.
4. Пост-обработка: Enhance PP Prototype Quality & Эстетика
Пост-обработка transforms the rough-molded PP prototype into a usable product, solving problems like flash, неровные края, and poor surface finish.
4.1 Key Post-Processing Techniques for PP Prototypes
| Техника | Методы | Сценарии приложения | Стандарты качества |
| Обрезка | Ручная обрезка (ножницы, Утилита нож), Механическая обрезка (Ротари), Лазерная обрезка | Руководство: Маленькие партии (＜ 50 штук); Механический: Большие партии (＞ 100 штук); Лазер: Высокие прототипы (НАПРИМЕР., Медицинские компоненты) | Обрезанные края гладкие (Нет заусенцев); size deviation ≤±0.1mm |
| Сборка | Screw connection (Самоубивающиеся винты), Клейкая связь (PP special glue: acrylic-based), Ультразвуковая сварка (частота: 15-40кГц) | Screw: Прототипы нуждаются в разборке (НАПРИМЕР., тестовые приспособления); Клей: Прототипы герметиков (НАПРИМЕР., резервуары для воды); Ультразвуковая сварка: High-strength joints (НАПРИМЕР., Автомобильные детали) | Joints are stable (no loosening under 10N force); airtight joints pass 0.3MPa pressure test |
| Поверхностная отделка | Шлифование (800-1200 Грит наждачная бумага), Полировка (полировка паста + тканевое колесо), Покрытие (гальванизация: никель, хром) | Шлифование: Remove scratches; Полировка: Улучшить глянец (НАПРИМЕР., декоративные прототипы); Покрытие: Enhance wear resistance (НАПРИМЕР., handle prototypes) | Шероховатость поверхности RA ≤0,8 мкм; no residual sanding/polishing marks |
| Рисование & Печать | Распылитель (акриловая краска), Silk-screen printing (ink: PP special type), Печата прокладки | Рисование: Change color (НАПРИМЕР., colorful toy prototypes); Печать: Add logos/text (НАПРИМЕР., packaging prototypes) | Paint film is uniform (thickness 10-20μm); printing is clear (no blurring, пилинг) |
5. Контроль качества: Ensure Consistency & Reliability of PP Prototypes
Контроль качества runs through the entire processing process of PP blow molding prototype parts, ensuring that each prototype meets design requirements and performance standards.
5.1 Full-Process Quality Control Measures
| Control Stage | Inspection Items | Методы & Стандарты |
| Material Incoming | PP resin grade, additive content, Свойства материала | Check material certificates; test tensile strength (≥30MPa) and impact strength (≥5kJ/m²) via universal testing machine |
| Processing Process | Толщины парисона, blow pressure, время охлаждения | Use laser thickness gauge (variation ≤8%); monitor pressure gauge (0.5-1.0МПА); record cooling time (5-15с) |
| Пост-обработка | Trimming accuracy, assembly stability, поверхностная отделка | Measure with caliper (± 0,05 мм); conduct pull test (joints withstand ≥10N); check with roughness tester (Ра ≤0,8 мкм) |
| Finished Product | Точность размеров, толщина стены, дефекты (пузырьки, трещины) | Use CMM (dimensional tolerance ±0.05mm); ultrasonic thickness gauge (uniformity ≤8%); 100% Визуальный осмотр (no visible defects) |
7. Yigu Technology’s Perspective on PP Blow Molding Prototype Processing
В Yigu Technology, мы фокусируемся на “design-process-quality integration” for PP blow molding prototypes. We select block Co-PP for impact-resistant prototypes, matching 0.2% antioxidants and 0.3% nucleating agents via 8+ material tests. In design, we use CAD modeling with DFM optimization to reduce 30% processing defects. For blow molding, we adopt intelligent parison controllers (thickness variation ≤5%) and dual cooling systems (shorten 20% время охлаждения). Quality control uses 100% CMM inspection and 20% sampling durability tests. The core is leveraging PP’s properties to balance efficiency, cost and performance—each step is optimized for practical application needs.
Часто задаваемые вопросы
1. Why is the wall thickness of my PP blow molding prototype uneven?
Uneven wall thickness is mainly caused by unstable parison extrusion or improper blow pressure. Первый, check the parison controller—use a laser thickness gauge to measure 5 points on the parison and adjust the die gap to reduce thickness variation to ≤8%. Второй, optimize blow pressure: для тонкостенных помещений, increase pressure by 0.1MPa; for thick-walled areas, decrease by 0.1MPa. Также, ensure the mold is evenly cooled (check water circulation in the mold).
2. How to improve the impact resistance of PP blow molding prototypes?
To enhance impact resistance: 1) Choose block Co-PP (impact strength ≥8kJ/m²) instead of homo-PP; 2) Добавлять 5-10% elastomer additives (like EPDM) to the PP material; 3) Optimize design—avoid sharp corners (set R≥3mm) Чтобы уменьшить концентрацию стресса; 4) Ensure sufficient cooling time (extend by 2-3 seconds for thick-walled prototypes) to improve crystallization uniformity.
3. What is the best post-processing method for assembling large PP blow molding prototypes?
For large PP prototypes (НАПРИМЕР., 1m-long pipe fittings), ultrasonic welding is the best choice. It uses high-frequency vibration (20-30кГц) to bond parts, creating joints with tensile strength ≥35MPa (close to PP’s own strength). Compared with adhesive bonding (slow curing, низкая сила) and screw connection (many parts, easy leakage), ultrasonic welding is fast (cycle time 10-20s), airtight, and suitable for large-batch production. Ensure the welding surface is flat (Ра ≤1,6 мкм) for better bonding.