Ideal state of injection molding machine for product control is to directly control size, quality, apparent quality and mechanical properties of product to feedback control feedback signal. However, for the moment, direct measurement and conversion of these non-electrical quantities into electrical signals has not been solved, so it can only be solved by controlling controllable variables of injection molding machine that affect quality of above products, mainly including:

2. Cut the plastic bottles into small pieces using scissors. Make the pieces small enough to fit inside the metal container.

Most of us simply toss empty plastic bottles away without a second thought. However, learning to melt them with a toaster oven and mold them is an inexpensive hobby that will let you explore your creative side while also giving those bottles a brand new existence. You can make a myriad of different things, from jewelry to figurines to holiday decorations, and are limited only by what your mind can conceive.

Precision injection molding machines refer to molding machinery suitable for forming precision plastic products. How to measure or judge a precision injection molding machine?

3. Place the pieces of plastic into an oven-safe metal container. To prevent melted plastic from spilling inside the toaster oven, do not overfill the container.

For variable pump injection molding machine, since pressure and flow output of oil pump are adjusted by swashplate angle of oil pump, it has high responsiveness and high responsiveness, repeatability of oil pump can reach 0.2% or less.

2. Place the metal container in the toaster oven for three to four minutes. Increase heat in 25 degree intervals until the plastic is completely melted. Different types of plastic have different melting points.

Most of precision injection molding is done under high injection pressure and high rate of injection (connector or mobile phone button). Filling time is very short, generally only a few tenths of a second. This requires system to have high response performance, otherwise response will be delayed, eventually leading to a large deviation between output signal of system and input signal. Molding process is difficult to debug, which will directly affect size or weight stability of workpiece during production.

Taking PC as an example, ordinary machine has a injection pressure of 177 Mpa, which can form a product with a thickness of 0.8 mm, and a precision machine with a injection pressure of 392 MPa can form a product with a thickness of 0.45 mm or more. Ultra high pressure injection molding machines can obtain products with a larger flow length ratio.

(4) Injection system pressure, installed on injection cylinder with a strain sensor, detecting periodic signals, measuring injection pressure, holding pressure and back pressure signal;

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3. Remove the metal container from the toaster oven using protective gloves or oven mitts once the plastic is completely melted.

In order to achieve rated injection rate, there are two ways: one is to increase maximum injection pressure of system; the other is to modify parameters of injection device or injection system, including screw parameters;

To make your own molds, try forming clay around one half of an object, then the other half. Place the two halves together, leaving a hole in the top where the plastic will be poured. Then fire the clay mold in an oven to harden it. You can also buy molds at craft stores, but for best results choose a mold that is lined with aluminum.

1. Remove all labels from the plastic bottles. Wash and dry the bottles thoroughly to ensure all of the sticky residue is gone.

As already mentioned, injection molded products have been applied to various fields and are widely used to replace high-precision metal parts, thereby placing strict requirements on dimensional accuracy, quality accuracy, apparent quality and mechanical properties of injection molded parts. At the same time, higher requirements have been placed on process factors affecting quality of injection molded products.

2. In direct compression type clamping mechanism, mold section oil passage and injection section oil passage are separated.

1. Oil system requires use of proportional pressure valves, proportional flow valves or closed-loop variable pump systems.

Ordinary injection molding machine: 147 ~ 177Mpa; precision injection molding machine: 216 ~ 243 Mpa; ultra high pressure injection molding machine: 243MPa or more, usually between 243 ~ 392 MPa.

High responsiveness of injection molding machine depends on scan time of controller, response time of oil pump and oil valve. For hydraulic systems with servo valves, there are considerable advantages in terms of response and repeatability.

Change of oil temperature of injection molding machine leads to fluctuation of injection pressure. It is necessary to use a cooling device for hydraulic oil to stabilize oil temperature at 50 to 55℃.

Precision injection molding machines require high injection speeds. Injection speed of precision hydraulic injection molding machines is required to reach 200mm/s or more, and injection speed of all-electric injection molding machines can reach 300mm/above.

Injection pressure has the most obvious effect on mold shrinkage of product. When injection pressure reaches 392 MPa, mold shrinkage rate of product is almost zero. At this time, accuracy of product is only affected by mold control or environment. Experiment proves that injection pressure is from 98 to 392 MPa, and mechanical strength of workpiece can be increased by 3 to 33%.

When temperature control system is heated, overshoot amount is small, temperature fluctuation is small. Precision injection molding uses PID proportional, integral, and differential temperature control to achieve a temperature accuracy of ±1℃. Temperature control accuracy of ultra-precision injection molding machine is ±0.1℃, and temperature deviation can be stably controlled between ±0.2℃.

(1) Temperature of each section of screw melting cylinder, non-periodic signal, generally at least 4 sections of heating;

(1) Due to high injection pressure of precision injection molding machines. This requires a high stiffness of clamping system. Parallelism of moving and fixed templates is controlled in the range of 0.08 to 0.10 mm.

1. Requirements for repeatability (reproducibility) of injection molding parameters are high, and multi-stage injection feedback control should be adopted.

2. Clamping system has sufficient rigidity and clamping precision. So-called clamping precision refers to uniformity, adjustable, stable and repeatable of clamping force, position accuracy of opening and closing mold is high;

4. Hydraulic system of precision injection molding machine should fully embody machine-electric-liquid-integration project.

(8) Injection speed is at least 4 levels of setting curve and feedback signal detection, displacement variable is converted to speed feedback, and feedback control is performed.

3. Pressure, flow, temperature, metering can be controlled to precise accuracy. Multi-stage injection can be used to ensure reproducibility of molding process and repeatability of product.

Usually precision injection molding machines have two indicators: one is repeated size deviation of product; the other is repeated weight deviation of product. The former is difficult to compare due to size and thickness of product; the latter represents comprehensive level of injection molding machine.

Generally, weight error of ordinary injection molding machines is about 1%, and better machine can reach 0.8%. Below 0.5% is a precision machine, less than 0.3% is an ultra-precision machine. As mentioned above, precision injection molding machines require product dimensional accuracy to be generally within 0.01 to 0.001 mm.

Using different colors of plastic bottles can create interesting effects. Experiment with colors when crafting with melted plastic. For example, to make gum drop Christmas tree ornaments, try pouring red and green plastic into shot glasses.

At present, injection molding machine generally adopts full computer control, and functions are gradually improved. It has intelligent functions such as “human-machine dialogue”, fault self-diagnosis, molding status monitoring, and SPC quality monitoring. Hydraulic system of injection molding machine is power component of each action of injection molding machine. Controller is hydraulic system control center, and all kinds of instruments are auxiliary monitoring part of running state of machine. Injection molding machine is actually an intelligent combination of machine, electricity, liquid and instrument.

Hydraulic system of injection molding machine needs to use proportional pressure valve, proportional flow valve to achieve different working pressure and flow of system. Whether it is fixed pump hydraulic system or variable pump hydraulic system, there are proportional valves to control working pressure and working flow of oil pump output, achieve proportional linear adjustment.

(4) Plasticized parts: screw, screw head, check ring, barrel should be designed into a structural form with strong plasticizing ability, good degree of homogenization and high injection efficiency; screw drive torque is large and can be continuously variable.

Mold temperature has a considerable influence on later heat shrinkage of part, affects apparent quality and crystallinity of part, and also affects mechanical properties of part. If cooling time is same, thickness of product having a low mold cavity temperature is greater than thickness of product having a higher temperature.

(2) It is required to protect low-pressure mold and control accuracy of clamping force. Because size of clamping force affects degree of mold deformation, it will ultimately affect dimensional tolerance of part.

(3) Pre-plastic displacement of screw, and periodic signal is detected by displacement electronic ruler, thereby extracting speed signal;

Accuracy of displacement sensor is required to be at least 0.1 mm, so that metering stroke, injection stroke and thickness of residual mat (injection monitoring point) can be strictly controlled to ensure accuracy of each injection and improve molding accuracy of product.

4. Pour the melted plastic into a mold using a wooden stick. Allow the plastic to completely cool before taking it out of the mold.

1. Take the toaster oven outside and heat to 250 degrees Fahrenheit. Melt plastic outside in order to avoid exposing yourself to harmful fumes.

Based in Colorado, Gisela Chavez has been writing and editing since 2004. Her editorial experience ranges from editing technical documents to editing for “The Bloomsbury Review.” She earned a professional writing certificate from the University of Colorado, where she received a Bachelor of Arts in English and Spanish.

This requirement is for a direct pressure injection molding machine because direct pressure injection molding machine starts to inject melt and fill mold cavity immediately after high pressure is applied. At the same time, oil must be filled with clamping cylinder to form a high clamping pressure. Otherwise, middle plate will retreat due to filling pressure and mold expansion force, which is not allowed. This requires that mold clamping oil line and injection oil circuit are separated. Otherwise, oil pump overload problem occurs due to oil filling clamping cylinder and injection cylinder at the same time, injection speed and system stability are affected.