H13 Steel High Temp Molds

We manufacture H13 Steel High Temp Molds for demanding materials and processes (e.g., thermosets, high-heat plastics). Our advantage is Thermal Integrity, with H13 tool steel offering superior resistance to heat checking and high-temperature cycling. Tooling Design incorporates robust cooling lines and venting. Advanced Technology ensures the mold maintains structural integrity under extreme conditions. Our H13 Steel High Temp Molds guarantee durable and optimal performance.

Let's take a comprehensive and in-depth look at the injection molding of PMMA (polymethyl methacrylate, commonly known as acrylic or plexiglass).

PMMA is renowned for its exceptional optical clarity, high surface hardness, excellent weather resistance, and good chemical resistance. This makes it highly popular in applications requiring high transparency and aesthetics, such as optical lenses, light guides, automotive taillights, instrument panel covers, display housings, and cosmetic containers.

The injection molding process demands extremely high precision and cleanliness; any negligence will be clearly revealed in the transparent finished product.

Подробное объяснение процесса литья под давлением ПММА

Этап 1: Предварительная формовочная подготовка (критическая)

This is the most critical step in the success of PMMA injection molding. Without proper preparation, all subsequent efforts will be in vain.

Выбор сырья и предварительная обработка (критично! критично! критично!)

Material Selection: Select injection-molding-grade PMMA granules based on product requirements. Common grades include Chimei's CM-205 and CM-211, and Mitsubishi's VR series. Different modified specifications may be available, including UV resistance, antistatic properties, and high flow properties.

Сушка и осушение: ПММА — очень гигроскопичный материал, поэтому к этому следует относиться очень серьезно.

Why is drying necessary? PMMA granules absorb moisture from the air during storage and transportation. If these granules, which contain moisture, are directly injected into the mold, the moisture will vaporize at high temperatures, resulting in indelible silver streaks (silver streaks), bubbles, and cloud-like haze. This can also cause polymer hydrolysis, leading to a decrease in molecular weight, brittleness, and a sharp deterioration in mechanical properties.

Drying Process: A dehumidifying dryer must be used (conventional hot air dryers are ineffective), drying continuously at 80-90°C for at least 2-4 hours. The moisture content of the dried granules must be below 0.03% (ideally <0.02%).

Note: Dried granules will quickly regain moisture when exposed to air. Therefore, the drying hopper should be directly connected to the injection molding machine inlet and kept tightly closed. If the machine is down for more than 30 minutes, the hopper may need to be re-dried.

Подготовка формы

Mold Design: The cavity surface must be mirror-polished (#10000 or higher diamond paste polish). Any minor scratches will be replicated on the part surface. Runners and gates should be smooth, free of stagnation points, and minimize weld marks.

Mold Cleaning: Before closing the mold, the cavity must be thoroughly wiped with a dust-free cloth, high-purity alcohol, or a dedicated mold cleaner. Any trace of dust, oil, moisture, or residue from the previous mold can cause fatal defects.

Mold Temperature Controller (Mold Temperature Control): Prepared to preheat and maintain the mold at the optimal temperature (typically 60-80°C).

Этап 2: Цикл литья под давлением (точный контроль)

Process parameters are set based on the principles of "gentle and uniform," avoiding any harsh operations that could cause material decomposition or stress.

1. Закрытие формы

Форма фиксируется под высоким давлением.

2. Впрыск и давление выдержки

Температура ствола: ПММА имеет узкий диапазон температур обработки, обычно устанавливаемый в пределах 210–270°C.

Слишком низкая температура: расплав имеет плохую текучесть, что приводит к неполному заполнению, появлению следов поверхностного течения и заметным линиям сварки.

Слишком высокая температура (выше 280°C): Материал может разлагаться, может появиться пожелтение, пузыри и черные точки.

Скорость впрыска: рекомендуются средние и низкие скорости впрыска.

High injection speeds can easily cause high shear stress, leading to shear overheating, localized material decomposition (producing black specks), and gas entrainment.

Slow injection speeds facilitate degassing, reducing bubbles and silver streaks, but may also make weld lines more noticeable. Finding a balance depends on the product structure. Multi-stage injection molding is typically used, with slow filling speeds in thick-walled areas to facilitate degassing and fast injection speeds in thin-walled areas.

Holding Pressure: Use medium to low holding pressures and short holding times. Excessively high holding pressures and long holding times can generate significant internal stresses, making the product susceptible to stress cracking during subsequent use. The primary purpose of holding pressure is to compensate for shrinkage, not to compact the product.

3. Охлаждение

Температура формы: это очень важно и обычно ее следует поддерживать в пределах 60-80°C.

If the mold temperature is too low, the melt rapidly cools upon contact with the cold mold wall, "freezing" the molecular chains. This results in poor flow, weak weld lines, and extremely high internal stress in the product.

If the mold temperature is too high, the cooling time is prolonged, production efficiency is low, and mold sticking is likely to occur.

Время охлаждения: убедитесь, что продукт полностью охлажден и сформирован, чтобы предотвратить деформацию во время выброса.

4. Открытие и выброс пресс-формы.

ПММА — хрупкий материал с высокой поверхностной твердостью. Система выброса должна быть сбалансированной и однородной.

Avoid using sharp ejector pins. It is recommended to use large-area ejectors (strippers), push blocks, or gas-assisted ejection to prevent white spots, cracks, and obvious ejection marks.

Этап 3: Постобработка и проверка

Gate Removal: Carefully cut or punch out the gate and runners. Trimmed areas should be ground and polished to restore transparency and aesthetics.

Отжиг (снятие стресса — настоятельно рекомендуется)

Purpose: Eliminate internal stresses generated during the injection molding process, significantly improve the product's chemical resistance (especially solvent resistance) and dimensional stability, and prevent future stress cracking.

Process: Place the product in a circulating air oven, slowly heat it to 70-80°C (10-20°C below the heat distortion temperature), hold it there for 2-4 hours, and then slowly cool it to room temperature. Rapid heating and cooling will introduce new stresses.

Обработка поверхности (опционально):

Полировка: изделия с незначительными дефектами поверхности или следами от литника полируются для восстановления зеркального блеска.

Твердое покрытие: иногда выполняется распылительная закалка для повышения устойчивости поверхности к царапинам.

Полная проверка и упаковка

Appearance Inspection: 100% inspection is conducted under a backlit inspection light, carefully checking for any defects such as silver streaks, bubbles, black spots, scratches, shrinkage, weld marks, and impurities.

Проверка размеров: используйте штангенциркуль, проекторы и другие инструменты для проверки важных размеров.

Проверка производительности: такие испытания, как пропускание света и дымка.

Packaging: Individually isolate and package items using soft materials (such as PE bags, foam pads, or paper interlayers) to prevent scratching. Operators must wear gloves.

We are a pmma injection moulding manufacturer, providing high-quality pmma injection moulding manufacturing. As long as you want to customize/develop pmma injection moulding products, you can find us. We have professional injection mold design and mature manufacturing technology, providing you with one-stop service, from product design-mold making-product production-product packaging-product transportation, we can help you in every link. As long as you come to us, we will provide you with the ultimate service and satisfy you in terms of product quality, production time, information dialogue, etc.

Изготовление пластиковых литьевых форм

Характеристики пластикового формования

Конструкция пресс-формы:

Процесс транзакции:

Тестирование пресс-формы:

Упаковка продукта

Фабрика

We are Custom Plastic Mold factory. Our factory is plastic injection mold maker. we has 17 years of experience in professional custom plastic mold and 10 years of foreign trade experience. We are custom Plastic Mold supplier. We can provide custom Plastic Mold service. Our factory can make the Injection molded plastic parts, and the quality of the products will satisfy you.

We have more than 50 high-end machines and hundreds of engineers and designers. We can provide one-stop service, from product design - mold making - product production - product packaging - transportation. We have a complete production chain. We can meet all your requirements.

Услуги, которые мы предоставляем:

Professional custom mold service, Plastic mold design and manufacturing .plastic product production, product design, mold design, blow mold customization, rotational mold customization, die-casting mold customization. 3D printing services, CNC manufacturing services, product packaging, customized packaging, shipping services.

We always adhere to the principles of quality first and time first. While providing customers with the highest quality products, try to maximize the production efficiency and shorten production time. We are proud to tell every customer that our company has not lost any customer since its establishment.If there is a problem with the product, we will seek a solution actively and take responsibility to the end.

Часто задаваемые вопросы

В1: вы торговая компания или производитель?

О: Мы производители.

В2. Когда я могу получить предложение?

О: Обычно мы указываем цену в течение 2 дней после получения вашего запроса.

Если вам очень срочно, пожалуйста, позвоните нам или сообщите нам по электронной почте, чтобы мы могли сначала предложить вам цену.

Вопрос 3. Как долго занимает время изготовления плесени?

О: Все зависит от размера и сложности изделия. Обычно срок выполнения составляет 25 дней.

Вопрос 4. У меня нет 3D-чертежа, как мне начать новый проект?

О: вы можете предоставить нам образец литья, мы поможем вам завершить дизайн 3D-чертежа.

Вопрос 5. Перед отправкой, как убедиться в качестве продукции?

О: если вы не приедете на нашу фабрику и у вас не будет третьей стороны для проверки, мы будем вашим инспектором.

We will supply you a video for production process detail include process report, products size structure and surface detail, packing detail and so on.

Вопрос 6. Каковы ваши условия оплаты?

A: Mold Payment: 40% deposit by T/T in advance, 30% second mold payment before sending out the first trial samples, 30% mold balance after you agree the final samples.

B: Оплата производства: 50% предоплата, 50% перед отправкой готового товара.

В7: Как вы делаете наш бизнес долгосрочным и хорошим отношением?

А:1. Мы сохраняем хорошее качество и конкурентоспособные цены, чтобы гарантировать нашим клиентам выгоду от продукции самого высокого качества.

2. We respect every customer as our friend and we sincerely do business and make friends with them, no matter where they come from.