Archive | Injection Molding

Understanding Molded Plastic Parts Manufacturing: From Concept To Fulfillment

When you’re looking to design a plastic part or entire plastic product, the process generally follows a simple series of steps. However, the method of production you end up using may be any one of several which is determined by the geometry of the part and the functional requirements placed upon it. It’s important to understand molded plastic parts manufacturing.

Fortunately, the steps are pretty straightforward once you understand the sequence of events needed to take a project from an initial idea to a final part design and manufacturing process. Below is a simple road map to consider and some examples of a couple of the most common molded plastic parts manufacturing methods. Go from initial design to a completed product.

1. Coming Up With A Design

The first step is coming up with a design for your plastic molded part. This can begin with something as simple as a sketch on the back of a napkin. Your initial design should ultimately incorporate enough detail to have an engineer draw up a 3D Model of your proposed plastic part. This is the beginning point from which you will make all the changes and refine the initial ideas into a working representation of your parts. Also from this drawing you may want to get an actual prototype built.

During this phase it is very helpful to work with a design team, which generally includes engineering, sales and manufacturing technical expertise, to assist with finalizing your design and preparing it for the next phase of the process. It’s important to define what type of testing needs to be done to prove out the feasibility of your part design and functionality.

2. Determine the molding process to be used.

Screw Driver Set — Tools/Hardware

Bellows

During this phase you’ll need to decide which type of molding method will be best for your product. The type of plastic molding process selected will depend upon your initial design, quantities needed and overall functionality of the part. There are several plastic molding processes available. Five of the more common general broad categories are Injection Molding, Blow Molding, Rotational Molding, Extrusion Molding and Thermoset Molding. Each of these processes have more specific sub groups of processes within them. The general category is all you will need at the beginning of your project. From these categories you will quickly narrow to the primary molding process most appropriate to your part.

Two of the most common forms of molding plastic include blow molding and injection molding. Injection molding is used to produce parts made with a simple open and close function of the mold. Wall thickness and close tolerances can generally be held more consistent with injection molding than blow molding. Blow molding is used to produce hollow plastic parts and can accommodate unusual shapes. Both injection molding and blow molding can use a very wide range of resin materials that exhibit a similar wide range of physical properties, both visually and to the touch. Impact strength, flexible toughness, pliability, and many other characteristics can be achieved by both injection and blow molding.

3. Prototype Your Design

During the prototyping phase, if your budget allows, you’ll develop a plastic prototype that will resemble the final molded plastic part. The plastic prototype may be created using rapid prototype resin printing, soft tooling, or use single cavity pull-ahead tooling. There are many prototype processes available today. The design team will determine the best fit for your project.

The budget for your project will also influence the number of times you can afford to go back and forth between your mock-up design and initial prototype. You want to keep the number of iterations to a minimum. You will be working closely with the designers and product engineers at this stage. The manufacturing team will play a large role in guiding what can and cannot be molded using the various plastic molding technologies.

Once you’ve finalized your prototype you’ll move forward to getting the final mold designed for your plastic part or product. You will now be working with tool design engineers to determine the most appropriate way for your part to be arranged in the actual tool, also referred to as the mold. This process should, if at all possible, include the manufacturing technical team to determine how a tool, or mold, should be designed to run properly in the molding equipment from which the part will ultimately be produced.

4. Manufacture Your Item

The plastic manufacturing company you use to produce your final plastic part will depend upon many factors. The type of molding you’re going to use for your final product, such as size of part and annual projected quantities will lead you to the group of processors for consideration. Most manufacturing facilities have specific specialties at which they excel. Some plastic molding companies do just the part manufacturing. Others do secondary assembly. Some manufacturing companies take the process all the way to finished goods. Fulfillment including packaging and shipping is not available from all molded plastic part manufacturers. You will also want to discuss the volume of parts each plastic manufacturer can handle. Small plastic manufacturing plants may not be suited well for large volumes. Others specialize in short run, highly technical molding. SPI Blow Molding is one of the Custom Industrial Molders capable of very difficult challenges. We range from high volume parts for the agricultural industry to low volume parts for the Medical Industry. Large tanks for the recreational vehicle industry to small injection molded parts for the electronics industry. SPI Industries’ injection molding resume covers a very diverse range of products from plumbing fixtures to freight securement systems.

Early discussions with potential manufacturers about volume, turn around, types of plastic resins available and fulfillment is highly recommended. It’s important to work with a plastics manufacturing facility that has experience producing similar style plastic parts, or is proficient in the style of plastic molding your product requires. You will also want to consider if you simply need parts or if you need the project handled from concept to completion. You may consider location of a plastic molding facility. SPI Industries and SPI blow molding are located in the South West Region of Lower Michigan and North West Region of Indiana. SPI Plants produce plastic molded parts for companies located in more than simply the Great Lakes Region. Our customers are located throughout the country. Depending on the needs of the customer, location is not always the most important criteria.

5. Package The Goods

Once your molded plastic parts have been produced they may then be packaged and delivered to your facility for assembly and further distribution, or could be delivered directly to your customers. Discuss in detail your overall need for assistance with any and all steps in the manufacturing process.

Determine the role of your molded plastic part in the overall production of your finished goods. For instance, if the molded part is just one of many components and requires additional assembly or further steps in the production process, a decision must be made as to who will do the additional work. It could be the molder or it could be you as the customer. Talk to your plastic parts manufacturer about assembly capabilities offered. Secondary operations are now offered by most plastic molders. SPI Industries and SPI Blow molding offer assembly and final processing for several customers. From single part production to total contract manufacturing and fulfillment, whereby we ship directly to your customers from your orders supplied daily.

If the molded plastic part is a standalone product you’ll be able to immediately distribute the parts to your customers. This is generally not the case.

Some manufacturing facilities will handle all of the shipping for you, while other facilities will simply deliver the finished product to you, and you will have to handle the delivery and shipping to your customers.

If you’re ready to make a mock-up design, a plastic prototype, or have a question about the manufacturing process, get in contact with SPI Industries or SPI Blow Molding today. We can help guide you through the entire molded plastic parts manufacturing process.

Difference Between Injection Molding and Blow Molding

Most people in the plastics manufacturing industry are familiar with both blow injection molding and blow molding these days. However there is still some confusion by product designers and engineers new to the industry about the difference between injection molding and blow molding . The blow molding process has become a standard for specific applications and understanding the differences between these two plastic molding processes can save design, prototyping and production time. This of course results in money savings and increases the speed of completion and delivery of your plastic part.

There are several significant differences between injection molding and blow molding:

manufacturing process itself
tolerances and margins of error
design considerations
role of the process for intended result

Main difference between injection molding and blow molding:

Injection molding – produces a part that is solid such as a reusable coffee cup lid
Blow molding – produces hollow parts such as water bottles

The blow molding process can produce plastic parts with very complex shapes. However to achieve this the wall thickness may vary from place to place depending on how much the material has to stretch when it is being blown. The thickness of a plastic part created through injection molding is determined by the relationship of the mold and the core.

You will be farther ahead if you are able to determine the best molding process for your plastic product in the product development stage.

Be prepared to answer a lot of questions from plastic mold engineers:

How is your plastic part going to function?
Is it a stand alone item?
Is it a part that connects to other parts or works in tandem with other parts to achieve a result?
Does it need to pivot, move, expand, condense?
Is the weight critical to the function?
Will the part need to withstand extreme levels of cold or heat?
Does the item need to adjust to specific pressure levels or PSI?
Will the part hold fluids?
Does it need to be food safe?
Does it need to be flexible or does it need to be solid and rigid?
What length does the part need to be, width, depth?

Answering these questions when designing and manufacturing any item is good a idea. With items requiring plastic molding the large variety of plastics to choose from, the importance of accuracy, and the difference between injection molding and blow molding it’s best to determine these answers as soon as possible. When one millimeter size difference can make the item usable or unusable for its intended purpose, accuracy and creative solutions are required. That’s why we have engineers, right?

Custom Plastic Molding Solutions

Because of the many variable in producing molded plastic parts, nearly every part we produce requires a custom solution. Engineers review all variables based on the end use of the product.

Variables to consider in Molded Part Production:

type of plastic used
flexibility or strength
psi pressure rate required
withstand temperatures levels – hot or cold
wall thickness
product dimensions

Once these variables are considered the whole process will go much smoother and quicker. The use of 3D printers in the prototype stage helps to reduce time too. Designing molds and fine tuning them to perfection can take a few tries but once complete production can begin.

When injection molding is determined to be the best process for your plastic part once you have an approved mold you’re practically golden. The injection molding process begins, the product is produced and there is very little concern of production issues with the injection process.

Therein lies another difference between injection molding and blow molding. In the blow molding process getting the mold perfect is only part of the battle. During the blow molding production process there are many variables manufacturers must pay attention to. The iterative nature of the blow molding process lends itself to production variables.

Periodically checking the production line is important for quality control. If the plastic is stretched too much small pin holes or cracks in seals can result. Checking for wall thickness uniformity to ensure they are within the tolerances needed for the part to behave as it is intended is also critical. As an example, a plastic bellows is made to collapse when pressure is applied and then expand back to it’s original form once pressure is released. Consistent wall thickness helps the bellows to function correctly. If the plastic bellows collapses on one end faster than the other because the wall is thinner your plastic part may wear out quicker and may not function smoothly. Having sold process control systems in place will produce consistent parts with high quality function.

Blow Molding Production Concerns:

pinhole leaks
leaking seals
flexibility or strength
velocity or pressure of blown air
speed of the mold closing
process temperature
wall thickness
poor function
consistent product dimensions

You can learn more about the various plastic molding processes that are applicable to your product or new invention at Plastic news.

Do you have a new plastic product invention and you aren’t sure about which plastic mold process is the best solution for your item? Give SPI a call today, our engineers love a challenge! We will help guide you in the most appropriate and cost efficient plastic molding solution for your unique requirements.

Questions to Ask When Choosing a Michigan Plastic Blow Molding Company

example of plastic blow molded part for a toy

Plastic blow molded part for a toy wagon.

Plastic blow molding allows product manufacturers to mass produce items with precision and cost efficiency. Utilizing skillful design and engineering is the first step in developing high quality plastic blow molded parts with lower production cost. There are many other considerations when choosing a blow molding company for your plastic molded parts.

Standard & custom molds – If the blow molded part you need is a universal design such as bottles or jars there are often standard molds that can be used. Utilizing these readily available standard molds reduces time and cost in development. Unique shapes that require custom molds add additional steps to the blow molding process. Design, fabrication, prototyping, fine tuning and creation of the final mold takes time and increases cost. The benefits of developing a custom mold that will be used time and time again for a unique part will reflect savings in the long run. Attempting to fit a custom shape to fit the constraints of standard molds is often not feasible or can require changes in other parts of the end product to produce a high quality functioning part.
Prototype – Prototyping helps you perfect your design before you move into the higher cost stage of production. Engineers develop a design that meets the part specifications and ensures process ability. Engineers create molds, fixtures and product designs on computer aided design (CAD) systems. Dependent on timeframe and budget prototypes can be created in a variety of stages to suit your needs. From standard engineering to a 3-D plastic molded part or a prototype with final finishes in place from chrome, to textures, to final coloring, etc. You can choose what stages of review that is required for your project from concept models to functional prototypes. A popular prototyping option is 3-D printing. With quick results combined with inexpensive prototyping material costs, 3-D prototyping on 3D printers is revolutionizing product design and accelerating manufacturing lead time.
Plastic Blow Molding Types: The three types of blow molding include Extrusion Molding, Injection Molding, Stretch Blow Molding. All of the blow molding processes include melting of resin otherwise known as plasticizing. They all have inflation and cooling phases within a mold and all are ejected from molds. All three have specific application advantages. Many blow molding manufacturers offer more than one options. It is important to discuss pros and cons of each process for the application of your plastic blow molded part. Generally extrusion blow molding can offer lower costs because of the lower cost of material per unit weight and is well suited for low production runs. Injection molding is capable of producing small intricate parts and more than one material can be sued when utilizing co-injection molding. Stretch molding works great for holding beverages and is used extensively in PET water bottles, seams are less visible or nonexistent.
Industries – Blow molding serves the consumer and industrial product industries. Products for use by consumers are a large sector of blow molded products produced every day. From food storage, beverage bottles and cups, to agricultural sprayers, and garden equipment, games, beauty products, decorative gift items, household products such as chair bases used in furniture manufacturing, etc. Some blow molding companies focus on niche products or categories. It is not uncommon for blow molders and injection molders, to focus on a single industry, such as agricultural, lawn and garden or appliances. SPI Blow Molding and SPI Industries found combining these plastic molding service they could offer a more comprehensive package of solutions for their customers.
Materials and construction – There is an enormous variety of plastic resins to choose from. A wide range of resins have become available over the years to fill the ever increasing demands as plastic part diversity has exploded. The function and finish characteristics of a part dictate the type of resin best suited for the specific part. You will need a molder and material supplier working in concert to solve the most difficult applications. Do you need extreme light weight? Do you need food grade that can tolerate high heat environments? Do you need color fast UV stabilization, or a resin flexible enough to form a multitude of bellows shaped parts? Do you need a hard plastic resin for a theatre seat with double walled construction? From temperature, color, impact, flexibility, and life span an experienced plastic blow molder can provide guidance and recommend the best resin for your application.

Did you realize there was so much information about plastic blow molding? There are actually plenty more and we’ll be covering them in the next blog entry. Be sure to check in. Meanwhile, what other questions are considering as you are looking for a plastic blow molding company? Please post them below and check back for answers or contact us directly, we’re happy to help.

Polycarbonate Packaging – It’s only the beginning

Are you in need of a material for your new invention or updated product that has the look and feel of glass and is also strong, durable and bioinert? Do you need the material to be injection molded or blow molded? Polycarbonate plastic meets all of these requirements and more. Polycarbonate packaging is quickly replacing glass containers because of it’s durability, light weight, heat resistance and biologically inert properties.

Physical Benefits of Polycarbonate :

high transparency
glass like feel
good electrical insulator
heat resistant
flame retardant
high impact resistant
low scratch resistant
dimensional stability
lightweight (as opposed to glass)
strong
durable
biologically inert

Because polycarbonate is highly transparent to visible light with a better light transmission than many kinds of glass it is highly sought out for use in food packaging. An example of a polycarbonate packaging solution is a mid-Michigan company that specializes in bulk coffee for sale. Blow molded polycarbonate cylinders dispense coffee beans in self-serve stations in grocery stores throughout the Great Lakes region and the midwest. The ability to provide a container that is impact resistant, transparent, and safe for food storage is key when it will be used in high traffic areas and contain food goods.

As high of an appeal the transparency factor and FDA food grade polycarbonate is polycarbonate food packaging is just one use for this versatile plastic. Many industries and products that utilize molded plastic rely on the special qualities polycarbonate offers. Polycarbonate can be used in medical applications because of it’s ability to be sterilized using steam at 240 degree. Also niche applications like eyewear protect from UV light

From construction materials and automotive accessories to sunglasses, industrial grade polycarbonate is a highly versatile material that can also be extruded through blow molding processes, injection molding processes and more transformational techniques.

Light Cover (lens)

Industry Served with Polycarbonate Packaging:

Furniture – stadium seating lighting,
Appliance – refrigerator shelving, washer dryer parts
Automotive Industry – dome lights, headlamp lenses, lighting lenses, windscreens, visors for ATV’s and
Consumer Goods – drinking glasses, luggage, dishes,
Food and Beverage Industry – water bottles, liquids, condiments, etc.
Technology – Data Storage, DVDs, compact discs, and BluRay® discs
Electronic Components – e-readers, telecommunications, smart phones
Construction Industry – noise barrier walls, green house sheeting,
Lawn and Garden Industries – tables, water fountains..
Medical Applications – sterile pharmaceutical packaging and utensils

These days plastic, Blow molding, and Injection Molding news is often centered around the PET bottles and the great value polycarbonate, brings to packaging but it’s uses truly seem to be limited only by our imaginations. From safety glass panels, UV protected eyewear, automotive interior parts, and drinking glasses at your favorite brew pub, the varied applications polycarbonite lends itself to offer more opportunities to manufacturers in all industries in Michigan, the mid-west and throughout the United States.

Innovative blow molding polycarbonate packaging received rave reviews at this year’s plastics industry awards. Details of the winning designs are covered in this issue of Plastic News.

Give SPI Blow Molding or SPI Industries Injection Molding a call today to see if polycarbonate is the best solution for your newly designed product. Our rates are competitive and our quality can’t be beat.

Click for a quick quote on your blow molding project or injection molding project.

Benefits of 3D Printers for Plastic Prototypes

Do you have a product invention that you think is ready to go to market? Whether you are an established company or a start-up entrepreneur manufacturing plastic prototypes can be costly and time consuming. Historically many new product design concepts never hit the market because of the time and expense involved in creating the prototype to prove the value to investors or stockholders.

Most of the product inventors on Shark Tank would never be able to step foot on stage if they had to rely on traditional plastic manufacturing methods to make their first product prototype! Fortunately the techies have come to rescue to reduce plastic prototype manufacturing costs. Whether your product prototype will be used in the furniture, agricultural, lawn and garden or even appliance or automotive industry a 3-D printer can be a game changer. Inventors and companies with new product lines can now have detailed prototypes without the expense and time commitment of a full production.

Benefits of a 3D Printer for Plastic Prototypes:

considerably less cost
considerably less time to produce
no need to secure factory space
no production line set up
no jigs or fixtures or expensive dies required
low cost for supplies / prototype material
reduce or eliminate shipping and procurement cost
plastic prototypes can be created in less than a day

The 3D printer specifications for SPI Blow Molding and SPI Injection molding can be found here. A 3D printer can be the solution for many inventions or newly revised plastic parts. Whether the finished part or finished product will require blow molding or injection molding, SPI can provide a quick and inexpensive prototype in your hands within days. All that’s needed are the specifications for the plastic part or plastic product you want to manufacture. SPI will create a design based on your specifications and develop it for the 3D printer and you will have a prototype.

Once a 3D plastic prototype part is tested fine tuning can be done to the design until a final prototype is approved for manufacturing. Production of plastic parts and products can be handled through the SPI Injection Molding plant or SPI Blow Molding plant depending on the product design.

Inventors and designers rejoice – you don’t have to break the bank to get your new product to market when a 3D printer and plastic prototypes allow you to create mock ups inexpensively and quickly until you achieve the perfect product you envisioned.

custom • design support • engineering • molding