Here is how IMM manufacturers choose the plastic crate injection molding machines for you

When a production business of plastic crates comes to mind, people tend to find the machine manufacturers consulting. Yes, it is where the most professional ideas from, while sometimes machine manufacturers are short of hands and too busy in answering your questions. Manufacturers do know their machines well but takes time to learn your market and your products.

IMM manufacturers choose plastic crate injection molding machines only consider the details included but not limited to details about plastic crate styles pictures/design drawings with its length, width, height, weight, raw material type, your target production capacity(like how many pieces per day/hour) you need in your investment.

To help you switch from the languages of plastic crate details to them in IMM manufacturers’?eyes, some ideas/terms below enable you to become more professional in the field:

1. Molds first

Mold design drawings in all formats that you could reach, will be a great help in prompt matching of the right platen size from the selected injection molding machines models. As long as you have mold design drawings from your mold suppliers, you could always receive a recommendation of what tonnage plastic crates injection molding machines may need. Before making molds, you could ask for catalogs of the FB Series Fruit Basket Injection Molding Machine, or the BJ Series Injection molding machine for reference. They could help your mold manufacturers to have a specific idea of what specifications to fit. Especially suitable for the situation considering various molds for investment at one time.

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Mold size, mold thickness, and required clamping force are what are most concern in this situation.

2. Plastic crates injection molding machine first

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This is the situation in which the manufacturers need more details from you to locate/match all their injection molding machines’?specifications. Powerjet Plastic Machinery could offer you a whole set solution for your plastic crates projects. Let’s check here one by one with plastic crate details as mentioned above--plastic crate style pictures/design drawings with its length, width, height, weight, raw material type, your target production capacity(like how many pieces per day/hour) to the specification to the plastic crates injection molding machines accordingly.

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A. Shot Weight

Plastic crate weight is what first asked for in their production projects. This data could reach an estimation of the shot weight?of the plastic crates' injection molding machines. It is the material sum weight of IMM to shoot into molds, outside the molds, etc. (Sum weight of sprue, runner, and gate). Apart from this, the raw material will affect a bit for this data.

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Same style and construction, bigger measure(higher, wider, longer) plastic crates with bigger shot weight.

Same measurement, closed type with bigger shot weight than ventilated type.

Same style, construction, and measurement, raw material vary affect shot weight(PP, HDPE, virgin, recycled, etc.).

You may want to ask about shot weight, the below chart may help.

B. Clamping force

If being asked what tonnage of IMM you want to check, please don’t misunderstand. They are not mentioning the machine weight, but the clamping force. It is the force needed to hold the molds together properly but not over too much to damage the molds, which is applied by the clamping unit of the injection molding machines. This data is mostly shown by IMM’s model name or specification charts, so clients do not need to calculate. What clients need to calculate is the clamping force required in their actual production for their crates with designs.

Clamping force is always affected by factors of total project area(S) and total cavities pressure(P) of the plastic crates that you want to produce in one mold(OR one cycle). To have an estimated or exact calculation of clamping force(F), all factors that manufacturers need to know are product measurement, weight, gate size, and their position, number of gates, products’?wall thickness, viscosity of the plastic, and?injection speed. If you need to check for sure, the formulas following may help you.

a. Clamping Force(kg, represent by F)=Cavity Pressure(kgf/cm2, represent by P)*Total Projected Area(cm2,represent by S)

F=P*S

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b. Total Projected Area(cm2, represent by S)= Projected Area(of one cavity, cm2)*Number of Cavities

c. Cavity Pressure Calculation requires more details for consideration--

Cavity Pressure(represented by P):

Viscosity grade constants(represented by k): Table 1 is below for reference.

Wall thickness: wall thickness of products

Basic cavity pressure(represented by PO): Check Chart 2 curve from the relationship among Basic cavity pressure, Flow length, and Wall thickness.

P=PO*k

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The full formula is F=PO*k*S.

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Thermoplastics-groupings and viscosity grades for flow characteristics (flow ability).

In the case of plastic crates injection molding, the total projected area is calculated according to the plastic crates’?length and width, and the cavities in each mold. So you need to know how many pieces of plastic crates you may need in working days or even working hours to meet your target ROI. Raw materials which will be used in the project are important, they affect factors like the viscosity of the plastic, and what injection rate needs to be set for the machine. Most materials used for plastic crates are PP, and some will use PE material. Virgin material, recycled, or a mix of both are okay. But only need to focus on using one type of plastic resin.

C. Platen size

Platens on the injection molding machines are used to hold the molds, all molds need the platens big enough with bolt holes that fit and install molds well. All platen sizes and bolt-hole positions need to be figured out before having mold-design. And surely, mold sizes are required to be smaller than platen size, in length and width. Plastic crate sizes in total must be smaller than the platen size if the final choice is to have more than one cavity.

D. Space between tie bars

Molds not only need to be smaller than the platen size but also need to control the space between tie bars. So that molds or tie bars could not be damaged by friction when in the process of injection molding. Except for two-platen large injection molding machines from Powerjet can be side-loading of molds, most molds need to load from the top. The inner height of the workshop for crane operation needs to be taken into consideration.

Different Mold Installation: Toggle type IMM V.S. Two Platen type IMM

E. Max. mold height & Min. mold height

Maximum and minimum details are required before mold design. The mold thickness needs to be designed in between the max. mold height and min. mold height of the injection molding machines, to ensure enough space for mold installation or dissembling. That is the reason for asking?about the height of the crates,?as mold thickness is always bigger than the product height.

3. Plastic material kind

Plastic crates in the market may be produced from PP, PE material of a mix of different agents, considering what quality and features these plastic crates may hold. Plastic crate types vary in structure and application environment.

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One-time use or disposable kind of plastic crates tend to use reground material, which is always called PCR plastic. PCR stands for Post-Consumer Recycled material or Post-Consumer Resin. It includes rHDPE(Recycled High-Density Polythene), rPP(Recycled Polypropylene Plastic), and rPET(Recycled Polyethylene Terephthalate), the first 2 used a lot in plastic crate production. These recycled petroleum-based plastics are not bio-based plastic, but they could become biodegradable or in some way 100% reused plastic material, to cut down carbon footprint. And release the burden of high consumption of conventional petroleum feedstocks such as oil or gas. Fully balancing the investment and maintenance cost of equipment and raw materials, market target, and promotion needs, plastic crate manufacturers are better held to have a deep understanding of target markets and clients. ??

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IMM manufacturers like Powerjet care about what material you will use, new raw material, recycled material, or a mix of both? Not only from technical aspects but also from market aspects. Technically, the viscosity, fluid properties, and MFI(Melt Flow Index) greatly affect clamping force tonnage. Economically the raw material choice affects the ballpark of equipment investment. The greatest startup cost of your plastic crates project may lie in this. It involves major components choosing your plastic crates' injection molding machines, important finished technology/craftsmanship of each part, and even the IMM models choosing. Powerjet FB Series Fruit Basket Injection Molding Machines use bi-metal screw barrels, more wear resistance, and corrosion resistance to increase the lifespan of IMM.

4. Some client cases from Powerjet（Case Study)

Client case #1 Vegetable Plastic Crates Automatic Production Line with Powerjet FB Serie Injection Molding Machine

Client case #2 Plastic crates in production Automatical production lines

Client case #3 More updating...

Plastic crates production line solutions FREE quotation from POWERJET team.

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