How to Size a Machine and Tooling for Industrial Parts

06 Aug.,2024

 

How to Size a Machine and Tooling for Industrial Parts

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Today&#;s industrial blow molding machines are highly efficient and predictable and generally can be relied on to produce sophisticated parts from the first shot. But it&#;s still wise to brush up on some basic guidelines to help you get started with properly sized equipment and tooling, especially if you&#;re making a particular part for the first time.

First, consider closely the the part characteristics. Will it require flash only on the top and bottom? Or maybe the only way to make good parts will be to flash all the way around? Project the finished weight of the part, and then estimate the shot size, including flash.

Flash only on the top and bottom of the part will mean a complete shot weight about 25% to 40% more than the final trimmed part weight. If the flash is all the way around, this could increase the shot weight by upwards of 60%. I have seen that reach 100% in some parts, so be careful with your estimate.

Shot size and cycle time will also influence the output required of the extruder. Estimate the needed output capacity of the extruder at 80% of its maximum screw speed. And the extruder must be working well to ensure a low melt temperature. The hotter the material, the longer the cycle time.

The finished wall thickness of the part plays an important role in cycle time. If the wall thickness is 0.060 in. or less, the cycle time will be in the area of 40 to 50 sec. A wall thickness of 0.080 to 0.100 in. will result in a cycle of around 60 to 70 sec. Parts with walls of 0.120 to 0.180 in. could result in cycles up to 180 sec. These are only estimated guidelines; depending upon tack-offs, for example, handles and very thick areas of the part will influence the overall cycle.

Another matter to be carefully considered is the size of the accumulator head that your part and process will require. Here are some guidelines:

  • Determine necessary head tooling size. You might require larger head capacity than output needs alone would indicate, in order to get the proper head tooling size for the part.
  • Find out the parison layflat needed based upon top/bottom or all-around part flash. (Layflat = tooling diam. x 3.14 ÷ 2). This equation does not consider die swell or parison preblow inflation.
  • Factor in parison die swell. Normally, larger tooling diameters have smaller parison swell. Small tooling produces a larger percentage of swell.
  • Remember that competitive heads may produce different parison sizes for a given tooling size.
  • Determine if there is a limit on how much regrind can be put back into the finished part.
  • Based on maximum shot size, determine head capacity needed. Consider what other parts might be run in this machine.
  • Select tooling size based on head size. Determine if converging or diverging head tooling is needed. For dual heads, determine the required head center distance.

Next, you&#;ll need to identify the size of the mold, including any outriggers, cylinders for split molds, water connections, and blow pins. This is very important if you run dual heads with side-by-side molds on a fixed head center line. The platens must be sized to fit the molds on the head centerline.

Now you are ready to determine the clamp tonnage required to mold your part. I use this as a guide:

  • HDPE: 500 to 600 lb of force per linear in.
  • HMW-HDPE: 600 to 700 lbf/in.
  • PP homopolymer: 500 to 600 lbf/in.
  • PP copolymer: 600 to 700 lbf/in.

Next, calculate the pinch clamp force needed to seal the parison: Length of pinch x lbf/linear in. ÷ .

Find the blowing clamp force (to keep molds closed during air blow): Projected area of blown section x blowing pressure (around 100 psi) ÷ .

Remember that once you clamp up, the pinch clamp force ends and the blowing clamp force takes over. Don&#;t add these two values together.

For more information, please visit Custom Blow Molders.

 

About the Author

Robert Slawska has more than 45 years&#; experience in blow molding. His firm, Proven Technology Inc., Hillsborough, N.J., provides engineering/consulting services and equipment to industrial blow molders. He can be reached at (908) 359- or via at . 

How to Choose Blow Molding Machine

How to Choose Blow Molding Machine

If you are thinking that all the blow molding machines are the same, the reality is they have different qualities. The manufacturers are blow molding machine relies on the trusted and well-known source. And they will get the best machine.

It is not just to choose the best blow molding machine manufacturer, there are ways to check that you will get the best machine. For choosing the best machine, follow the below tips.

First is Equipment Size

Many times, customers didn&#;t worry about the size of the blow molding machine but some customers choose the wrong size. The customer has to focus on the size of the mold that how many types of products they make with it.

Capacity

The production capacity is an important factor for blow molding machines. Customers have to choose machines which have a capacity which matches according to their production capacity. After selecting the machine, the machine should have 25 percent more capacity and with this is how a business grows.

Automation

In today&#;s market, the different types of machines come with the latest features with more automation. The automation saves more money and time in business. Whatever the automation machine used wired relay logic or a PLC control, this makes the production smooth. Also, with this, the blow molding machine manufacturers show different operations of a machine. Manufacturers help customers to understand which type of automation is beneficial for their business.

Demo

The demonstration of a machine makes easy to choose from different blow molding machines. The well-known manufacturer arranges this with in-person or online. Also, if the customer is near to the manufacturing facility, they can visit the company and see the production and how the machine works. Or a representative of the company explains the machine and gives a demonstration through the internet. If there is an explainer video of the machine that how it works from start to end has higher chances of converting the inquiry into order.

Customers must be assured that they will get the best blow molding machine from Sadhi Machinery Plastic Products. We believe that every customer should get the best business with the machine. We provide the best business suggestions to our customers. For more details, visit our website or contact us.

If you want to learn more, please visit our website Chemical Bottle Blow Molding Machine.