Plastic Prototypes Using Silicone Rubber Molds
How-to, step-by-step instructions that take you from making the master pattern to making the mold and casting the plastic parts.
Prototyping has been around for a number of years. With the addition of one word, rapid, a new industry has been created. Economic concerns along with global competition make additive fabrication a must. An inexpensive and frequently used method in the prototyping process is casting urethane parts from silicone rubber molds. The urethane materials of today, along with moldmaking techniques from previous years, give prototyping the respect it deserves.
This article describes the techniques used to cast quality urethane parts from a silicone rubber mold using a five-step duplicating process:
What Is The Best Material To Make A Mold
Prestigious Competitive Price Plastic Manufacturing Address In China
With the rapid increase in demand for plastic products, plastic factories are also increasing day by day. Many plastic factories in China and across the country are ready to invest in modern equipment.
They constantly improve their staff and train skills to produce highly competitive products. Plastic mold making produced compete directly with imports from China.
With a system of high-quality plastic factories, as mold is a reputable plastic manufacturing facility on demand with competitive prices. The author of the article is looking forward to receiving contributions from readers so that the article can bring more value to the community.
You May Like: How To Remove Mold Toxins From Your Body
Making Your Own Plastic Molds
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.
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.
Things Youâll Need
Read Also: Cleaning Mildew From Bathroom Ceiling
Evaluate Products Based On Product Functionality
In general, different plastic products will have different functions. Based on the inherent characteristics of the product to evaluate such as:
- surface smoothness
The quality plastic products will be the manufacturer’s commitment to the full features above. When checking the product, if you do not meet the above requirements, you can claim compensation or complaint about that product.
Read Also: Who Do You Report Black Mold To
Designing A Plastic Injection Mold
The mould design determines the product shape and design. Companies should consider hiring experienced designers and engineers to design and build molds. The condition of a mold determines the success of the whole molding process and whether the product will have defects or will be perfectly produced. Before buying or creating a mold, some considerations need to be taken into account.
The gate: they wear out fast and when designing a mold, this needs to be put in mind. The gates need to be made with inserts that are replaceable and durable. The most common materials used in making these inserts are D-2 steel, CPM-10V, and carbide. The gate diameter should be sufficient enough for allowing passage of molten plastic to fill the cavity. The location of the gates should also be considered.
Sprues: the sprue orifice must always be larger than that of the nozzle so that to prevent any leakages during the process.
Mold material: molds are made from steel either hardened or pre-hardened, beryllium-core alloy, and aluminum. Choosing mold materials depends on cost. Steel costs more to build but is long-lasting compared to the others. Over time, steel will be less costly because it needs less replaceability.
Shrinkage: when designing a mold, one should consider the shrinkage allowance of the materials to prevent any defects on the final products.
Cooling system: the holes of the cooling system need to be made on both the cavity and core to minimize the cycle time.
How To Make Silicone Molds: A Practical Guide
Throughout history, artisans have used molds to make everything from Bronze Age weaponry to modern-day consumer products. While early molds were commonly shaped in stone, modern science has given rise to materials that are far easier to work with, such as silicone.
Today, a vast array of industries rely on silicone molding. Product developers, engineers, DIY makers, and even chefs all make silicone molds to create one-off or smaller runs of parts.
In this practical guide to silicone mold-making, well break down everything you need to know before getting started, provide a list of items youll need, and give you a step-by-step guide for incorporating silicone molds into any type of project.
Silicone Molding For Product Design
You May Like: Mold Spores On Bathroom Ceiling
You May Like: Can You Paint Over Mold In Bathroom
How Deep Cryogenic Treatment Works
Deep cryogenic processing works by bringing down a metals temperature to below -300F. From there, the metal is left in a cryogenic cooler for 24 hours or more, depending on the metal and the application.
This has the effect of altering the crystalline structure of a given metal to permanently relieve any stresses that the manufacturing process may have instilled in the metal.
Its important to do that as the temperature needs to be brought down gradually. In deep cryogenic treatment, its also possible to regulate the temperature and increase the amount of cryogenic material in the cooler as per the needs of the job.
At such low temperatures, the crystalline structure of the metal undergoes significant change. The next step is to slowly bring up the temperature in order to make these changes permanent.
With this stage, the stresses that were introduced in the metal in the machining process are released, thereby increasing the durability of the material.
Examples Of Polymers Best Suited For The Process
Most polymers, sometimes referred to as resins, may be used, including all thermoplastics, some thermosets, and some elastomers. Since 1995, the total number of available materials for injection moulding has increased at a rate of 750 per year there were approximately 18,000 materials available when that trend began. Available materials include alloys or blends of previously developed materials, so product designers can choose the material with the best set of properties from a vast selection. Major criteria for selection of a material are the strength and function required for the final part, as well as the cost, but also each material has different parameters for moulding that must be taken into account.:6 Other considerations when choosing an injection moulding material include flexural modulus of elasticity, or the degree to which a material can be bent without damage, as well as heat deflection and water absorption. Common polymers like epoxy and phenolic are examples of thermosetting plastics while nylon, polyethylene, and polystyrene are thermoplastic.:242 Until comparatively recently, plastic springs were not possible, but advances in polymer properties make them now quite practical. Applications include buckles for anchoring and disconnecting outdoor-equipment webbing.
Don’t Miss: How To Clean Mold Off Leather Furniture
Case Study: Using A Plastic Injection Mold To Create A Gutter Cleaning Tool
Recently, we had an entrepreneurial client come to us with an idea for a plastic part. He had jury-rigged an innovative gutter cleaner from parts he bought at a local hardware store. On his own, he produced about a dozen gutter cleaners. But he needed to scale his production to make the product commercially viable. He came to our team at Rex Plastics to find out whether plastic injection molding was right for his design.
After reviewing the hand-made prototype, we recommended that he use injection molding for the following reasons:
- The plastic part was smaller than 40g.
- The client needed to manufacture more than 1000 plastic parts per year.
- The plastic parts wall thickness was uniform.
- The plastic part could be made from a thermoplastic material.
- The function of the plastic part was more important than its aesthetics.
- The client could wait several months before starting mass production.
We were able to design a mold for the gutter cleaner, build a prototype, tool the mold, and begin production in just a few months.
Today, the client purchases thousands per year, and order quantities for his gutter cleaner are climbing steadily.
Check out our other case studies to understand how this process can work for you:
Simple Steps For Making Prototypes For Plastic Items
1. Create a Plastic Product Design
Having a concept or design is always the initial step in manufacturing. Whether you are creating a garment, electronic device or a a packaging product, creating the design and concept should go first and this is no different when it comes to plastic prototyping.
When creating a plastic product design, you should consider feasibility and functionality and make sure the concept is doable. If the design fails the latter then it would be a waste of time and youd end up creating a design from scratch.
You can collaborate with plastic experts at this stage and do 3D prototyping to make sure your plastic product design can be engineered for production. Knowledge from experts would come in handy and you can easily work altogether as long as you clearly inform them of the concept you have in mind. These files are usually made with one the various CAD softwares out there in formats such as stp or stl files. You can also make design concepts first or even animated videos that show the planned product from several sides and in contact. A good read is this list of the best animation software that you can use to animate your prototype.
2. Product Engineering
The parts should have walls with the right thickness with no undercuts to avoid the steel halves from cracking open or be stuck on one side of the steel tool. We will also determine the gate to which the plastic will be injected and further assess how the plastic material into the gate/s.
You May Like: How To Test For Toxic Mold Syndrome
Cut And Assemble The Form
When I make forms, I like to have two pieces of the material of my choice available- one that I can cut from and one that I will use as the base. You will want to cut the sides to be higher than the thickness of the table pour . Most tables are poured between 1.5 3. This means if you do a 4 side, you will not have to worry about the height of the walls for most pours you will complete while using this mold.
After you have cut the form, you will begin the assembly process. Place the walls of the mold on top of the base . Placing the walls on top will help mitigate leaking. It is less likely that epoxy will slip through a sealed form if it does not also have extra gravity playing a role. This will also help the base stay level.
To ensure that the form is sturdy and secured, I usually screw the walls in from underneath the base, making sure the screw heads have a divot to go into . This also helps prevent any slipping later on in the project.
Plastic Components Are Used In Many Industries From Automotive To Home Appliances And Medical Devices Components In A Variety Of Plastics Are Used To Protect Enhance And Build A Huge Range Of Products Yet Very Few Manufacturers Know Exactly How Their Plastic Components Are Produced
With its reliable, high-quality performance, injection molding is one of the most common processes used to produce plastic components. Indeed, the compound annual growth rate of the injection molded plastics market is expected to increase by 4.6% up to 2028.
Yet, despite its ability to produce high numbers of plastic components quickly, the injection molding process must be tightly controlled to maintain the quality of the final parts. This article will explain how injection molding works and how experienced manufacturers control the process to produce the best quality plastic components. We’ll cover:
Injection molding is a complex manufacturing process. Using a specialized hydraulic or electric machine, the process melts, injects and sets plastic into the shape of a metal mold thats fitted into the machine.
Plastic injection molding is the most widely used components manufacturing process for a variety of reasons, including:
This cost-effectiveness, efficiency and component quality are just some of the reasons why many industries choose to use injection molded parts for their products.
Also Check: How To Clean Mold From Patio Pavers
What You Need For Diy Injection Molding
Building a setup for DIY injection molding does require some investment. It takes both money and time to acquire the right equipment and to master using it. However, these costs are in many cases still lower than the cost of a single metal mold, so the eventual time and cost savings, once youre up and running, will easily offset the initial effort.
The Form 3 SLA 3D printer next to a Holipress desktop injection molder.
Heres what youll need to get started:
A benchtop injection-molding machine, such as the Galomb Model-B100 or the Holipress. There are a number of benchtop injection molders on the market that vary in cost. Many of the lower cost molders use a hand-driven plunger, while some of the more expensive units use a screw or pneumatic system. Some of our customers have recommended systems from Minijector, Morgan, APSX, or Micromolder as well. Desktop automated molders such as the product line from Babyplast are good alternatives for mass production of small parts.
Plastic pellets of your choice
A CAD software tool of your preference to design the mold insert, such as Blender, which you can .
Before purchase, make sure to evaluate the injection molder carefully against your production requirements. For large parts, industrial processes will still be necessary. This DIY injection molding technique is best optimized for producing small parts at low volumes.
A Formlabs 3D-printed mold, and encapsulated component, made using this DIY injection molding process.
The Structure Of An Injection Mold
The structure of an injection mold can vary depending on the specific application and design requirements. In general, however, an injection mold consists of the following main components:
Based on the molding process, the plastic mold is divided into
You May Like: How Does Black Mold Look
Tips For Using Plastic Blister Packaging As A Mold
This can be a good option for craft with casting resins on a budget. Clear blister packaging is easily had usually free or low cost with products youre already purchasing. The circular casting in the photo above was cast in a blister pack found in a parking lot of a Krogers. These thin plastics are made of PET and will definitely need a mold release.
In the castings above I used Johnson paste wax but silicone release spray might be better. The PET is not silicone so experimental dye and pigment explorations are not recommended ended. As you can see from the mishap I had on the rectangular tablet forms. Dyes, pigments, and fillers should be fully disperse in casting resin.
Also, it should be noted the life of these improvised molds will be limited so dont get to attached to any of them.
You May Like: How Do You Remove Mold From Leather
What Is The Injection Molding Process
In laymans terms, injection molding boils down to four simple steps:
But we cant talk about the injection molding process without discussing the injection molding machine. A plastic injection molding machine consists of four main parts:
Read Also: How To Check For Toxic Mold
How To Melt Plastic Bottles For Molding
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.
