Cannapaco specializes in injection, insert, and over-molding of a wide range of plastics, as well as being experts in working with elastomer resins. Our advanced capabilities and in-depth industry knowledge allows us to work as a single source solution for their manufacturing needs. From prototypes to high volume production, our state of the art equipment and facility gives us the flexibility to deliver precision molded products with rapid turnaround times.
Each plastic part requires a specific manufacturing process which can be significantly different from one product to another. Injection molding and blow molding are two core processes in plastic manufacturing. There are many types of manufacturing methods categorized under injection molding, such as thermoplastic injection molding, over molding, insert molding, cold runner molding and hot runner molding. For the blow molding process, Injection Blow Molding, Extrusion Blow Molding, and Injection Stretch Blow Molding are the most popular choices.
Injection molding is a manufacturing process widely used for plastic bottle production, which is also known for its high-volume production capacity, low cost per part and good tolerances. All thermoplastics can be injection molded with the most common materials being Polyethylene (PE) Polystyrene (PS), Polyethylene terephthalate(PET) and Polypropylene (PP). During the manufacturing process, polymer granules are first melted and then injected into a mold cavity to form the final shape of the container, where the liquid plastic cools and solidifies.
Raw Material:
Polyethylene terephthalate(PET)
Polystyrene (PS)
Polycarbonate (PC)
Polypropylene (PP)
Polyethylene (PE)
Manufacturing Process:
granules feeding through hopper-heated plastic filling barrel-injection of plastics through gates to cavity
-cooling and ejecting parts from open mold
Machine Type:
Injection molding machines, also known as presses, consist of a material hopper, an injection ram or screw-type plunger, and a heating unit
Clamping force: 5 to 6000 metric tons (Force that keeps the mold closed during the injection molding process)
Mold Characteristics:
Runner System Type: Hot Runner/Cold Runner
Mold Material: (Core) Stainless Steel 718/P20/SKD; (Body/Base): Stainless Steel H16/Aluminum
Number of Cavities: 1 to 256
Life expectancy: usually 1 to 10,000 million cycles
Push and Turn Child-Resistant Bottle
Pop Top Vials
The entire injection molding system primarily consists of a hopper, barrel with nozzle, presses, and the mold. The sequence of steps during the injection molding of a plastic container is as following: material preparation, clamping process, injection process, cooling process and ejection process. These 5 basic steps form an injection molding cycle.
An Injection molding machine, or (Injection moulding machine BrE), also known as an injection press, is a machine for manufacturing plastic products by the injection molding process. It consists of two main parts, an injection unit and a clamping unit.
The preparation starts with setting up the press, configuring the ejection and cooling system, and mold assembly. Then calculate the exact weight and volume of resins used for production, mixing it with masterbatch for desired color, and finally feed the granular plastic into the hopper.
The clamping unit of the injection machine holds the two halves of the injection mold together during the injection and cooling. This force will keep injection mold always closing under high pressure of injection process. Both halves are then attached to injection molding machine and one half can slide.
Once the two halves of the mold are closed, the plastic pellet is forced into a heated chamber from the hopper called the barrel where it is melted. The screw behind the barrel will start moving forward and push the melted plastic towards the end of the barrel, entering the injection mold from the nozzle of the barrel through a channel called sprue, and continuously passing through gate, runner and eventually reaching the cavity. The injection process ends when the cavity is quickly filled with melted plastic pellet.
Once the cavity is filled with the melted plastic the part is allowed to cool at a set temperature for a period of time to solidify the material. Cooling time can be calculated based on the thickness of the wall of the part, and type of resins used for injection.
When the resin is cooled, the mold will be open. Force and pressure needs to be applied to the part in order to eject it from the cavity as the plastic part shrunk and got sticky at the end of the cooling process. Once all the parts are ejected, the mold will be closed and another injection cycle will start again periodically.
Another form of manufacturing process for plastic container is blow molding. It is similar to the concept of glassblowing to produce hollow glass container in glassware manufacturing. In contrast to injection molding that final form of container is being shaped directly by the cavity, blow molding will first makes a preform or a parison and thereafter use the compressed air to blow the preform into the desired shape and size. There are in general 3 types of blowing process which is injection blow molding, injection stretch blow molding and extrusion blow molding.
Material:
Polyethylene terephtalate (PET)
Polypropylene (PP)
Polyvinyl chloride (PVC)
Polystyrene (PS)
Polycarbonate (PC)
Acrylonitrile butadiene styrene (ABS)
Manufacturing Process:
plastic resin–preform/parison–blow molding–final part
Blow mold forming process:
extrusion blow molding
injection blow molding
(injection) stretch blow molding
Oval Bottle
Straight Sided PET Jar
In extrusion blow molding (EBM) process, the plastic is melted and extruded to form a preform or a parison. A mold cavity which consists of two halves, closes around the perison where the compressed air is blown into the parison to inflate it eventually to its desired shape and size. When the container is completely shaped and cooled it will be ejected from the mold. EBM can be either continuous or intermittent. The continuous form is when parison is extruded continuously and each piece is cut off by a knife, whereas the intermittent form have a stop in between each mold.
In contrast to injection molding process where the container’s final shape of size is formed in a single step of polymer resin injection, injection mold blowing (IBM) process only produces the preform of the container first, which is a thick tube with a fully threaded on a core rod. The core rod is then rotated and clamped into the blow mold where the thick tube is blown and inflated by compressed air to its final shape and size. After the cooling process, the container will be ejected from the blow mold.
Injection stretch blowing molding process (ISBM) is very similar to injection mold blowing (IBM) process with the exception that the parison/preform of the container can be stretched biaxial in both hoop and axial direction during the blowing process. ISBM happens in either single stage or two stage, with the single-stage ISBM having the preform injected, stretched and blown in one machine, and two-stage ISBM having preform made first in a separate machine. Because of the biaxial stretching containers made through ISBM tend to be stronger in tensile strength compared to that through IBM and therefore saving money on material use by reducing the total weight of each container.
Injection molded parts have two sides: the A side, which faces the cavity where it has the gate, sprue and runner system(which will be explained later) and the B side, which faces the core (back half of the mold) where has the ejector system and therefore also where the parts stick.
A-side (Cavity): The cavity is the void inside the mold that the molten resins fill and form the shape of the plastic part, and therefore is also considered as the cosmetic side of the part. The number of cavities is the quantity of parts that a single clamping cycle can produce.
B-side (Core): The core is the interior and functional side of the mold where it contains the ejection system that pushes the plastic part out when it is completed.
The runner system is the path that directs the melted plastic into the cavity of the injection mold. It controls the material flows and pressure where the liquid plastic is injected into the cavity and will be removed after the part’s ejection. Usually, the following three parts form a runner system.
Sprue – It is the main channel and the starting point for the molten plastic material to enter the mold.
Runners – From the sprue, the resin flows through the runner to each cavity in the mold. The runner spreads the resins along the surface where the two halves of the mold meet and connects the spur to the gates.
Runners can also be hot or cold. In a cold runner system, the runner is constantly filled with the melted plastic and it is cooled, solidified together with the parts. The material in it is therefore a waste after the ejection of the parts in each injection cycle as a byproduct. By contrast, in hot runner system the material in runner will be heated, melted and recycled for the next injection cycle and therefore eliminate the material waster. In general, hot runner will save 15% – 30% material compared to cold runner by recycling the waste material in the runner.
Gates – At the end of each runner, the molten plastic enters the cavity through a gate that directs the flow. Gates come in many varieties and are explained in more detail below. A gate is the point where it connects the from the core to the runner and to cavity from the runner. It’s geometrical shape and location is important as it will determine the flow and pressure of the melted material in which runs through. Depending on the where the material is being injected, there are in total 4 types of gates: Edge Gates, Tunnel gates, Post gates, and Hot tips, for the edge gates being the most common one where the injection happens in the parting line of two halves of the mold.
The success of manufacturing a cost-effective plastic part with high quality relies on the optimal design of its injection mold. We have summarized here the most critical aspects to consider in mold design, as well as the common pitfalls to avoid.
One of the most critical design principles is to use uniform wall thicknesses throughout the part. Uniform walls aid in material flow in the injection mold and therefore minimize sinking, warping, and residual stresses. In addition, use thinnest wall thickness for cost saving purpose and consider adding ribs as well to replace using thick wall.
Sharp corners and edges should always be avoided during the mold design. They may cause in crack on plastic part due to abrupt rise in stress around the corner. Therefor we should add smooth radii in sharp corners.
All of the plastic part eventually has to be ejected from the cavity once it is formed. Therefore adding a slight angle to any surfaces that are parallel to the direction of the ejection of the part is required. The angle is called draft.
Once the design of the injection mold is completed, we are ready to start the process of injection mold manufacturing. Depending on its life expectancy, injection mold can be categorized as rapid injection mold, low-volume injection mold, and production injection mold. The main materials being used is either stainless steel or aluminum.
The manufacturing process will start with working on a bulk base, and the main methods used in here are Computer Numerical Control (CNC) machining and Electrical Discharge Machining (EDM).
The conventional machining includes lathe cutting, turning, grinding, milling and drilling, and the mold base will be machined into a desired shape. With the aid of computer-aided manufacturing (CAM) and computer-aided design (CAD) software, the manual machining work can be replaced to a high-precision programmed process.
EDM is important process in addition to CNC machining, since it can handle shape that is not possible to CNC machining. It uses an electrode to disperse the metal in the area that is opposite to the electrode. Pre-hardened steel can also be processed with EDM so there is no need of heat treatment which is required for CNC machining.
Once the main forming work is complete, it is the time to polish and apply finishing before the parts sent for inspection and assembly.
Material choices greatly impact the longevity and feasibility of your project, and the most important aspects to conside includes material properties, manufacturability characteristics, cosmetic appearance, and cost.
Polyethylene Terephthalate is a strong, lightweight plastic resin and form of polyester that closely resembles glass in clarity and takes colorants well. PET is commonly used in food packaging due to its strong barrier properties against water vapor, dilute acids, gases, oils and alcohols. PET is also shatter-resistant, slightly flexible and easy to recycle.
High Density Polyethylene is a rigid, tough and strong resin of natural milky color. HDPE has very good stress crack resistance as well as high impact and melt strength. HDPE is appropriate for personal care, beverages, food and chemicals. It lends itself particularly well to blow molding.
Polyvinyl Chloride is a widely-used plastic. PVC containers offer clarity, durability and chemical resistance. They are primarily used for household goods such as soaps and cleaners, chemicals and personal care items. The material is often used for pipelines in the water and sewer industries because of its inexpensive nature and flexibility.
Polypropylene is a thermoplastic polymer used in a wide variety of applications, including food packaging, textiles, laboratory equipment, automotive components, and polymer banknotes. It is unusually resistant to many chemical solvents, bases and acids. It is much less brittle than HDPE. Polypropylene has very good resistance to fatigue, so that most plastic living hinges, such as those on flip-top bottles (Tic Tacs), are made from this material.
Polystyrene comes in many shapes and forms, from foam egg cartons and meat trays, to soup bowls and salad boxes. It protects against moisture and maintains its strength and shape even after long periods of time.
Polylactide is a corn-based resin made by NatureWorks® PLA that requires significantly less energy to mold into plastic containers. It can be shaped into a variety of bottles, containers, trays, film and other packaging. The production of PLA uses 68 percent less fossil fuel resources than traditional plastics and it is the world’s first greenhouse-gas-neutral polymer. The properties of PLA are well suited for the injection stretch blow molding process used to form bottles and jars. PLA is primarily suited for short-shelf-life applications that use cold-filling techniques. It is successful as a bottle resin because of its transparency and its fit with all landfill diversion options.
The following chart compares characteristics for the most common types of resins used for plastic packaging. However, most data refers to tests done on sheets of resin (film) rather than rigid plastic bottles. For best results, we always recommend that our customers always test their product in actual bottles to ensure compatibility.
| Material | Clarity | MVTR* | O2** | CO2** | Impact Strength | Recycle Code |
| PET (Oriented or Stretch Blown Polyethylene Terephthalate) | Excellent | 2.0 | 75 | 540 | Good | 1 |
| HDPE (High Density Polyethylene) | Poor | 0.5 | 4,000 | 18,000 | Good | 2 |
| PVC (Polyvinyl Chloride) | Good | 3.0 | 150 | 380 | Fair | 3 |
| PP (Polypropylene) | Poor | 0.5 | 3,500 | 7,000 | Fair | 5 |
| PS (Polystyrene) | Excellent | 10.0 | 6,000 | 18,700 | Poor | 6 |
| PLA (Polylactide) | Very Good | 18-22 | 38-42 | 201 | Good | 7 |
With years of experience in packaging industry who focus a lot on the plastic container manufacturing, our state-of-art facility is well-equipped with most up-to-date press, CNC turning and milling machines, and CNC EDM to fulfill the need of our customer’s tooling and production request. Moreover, our clean room manufacturing facility is complied with the standards that is required for food and medical grade packaging. Our design and value-added services will complement with our production services to provide a true turnkey manufacturing fulfillment for our customers.
Our offshore manufacturing building is located in the manufacturing hub city Dongguan, China with a total over 100,000 square feet. Our plant is established in 1990 and now is a fully integrated facility that has corporate office, warehouse, tooling and machining shop, press room, inspection and quality control department and ISO certificated clean room.
Our tooling and machining room is the place where we handle all of the mold making request that we will be finished 100% in-house. Whether it’s mold making or post-mold decoration, We have 6 CNC EDM that is fully programmable, 3+2 axis CNC Vertical Milling center, CNC Horizontal Milling machine, Traditional lathe cutting machine, 3 Surface CNC Grinder, Laser Etching Machine, Hot Stamping Press and Pad Printers to fulfill any of your request.
Our production department is geared up with up-to-date equipment that are all microprocessor controlled. For the manufacturing process that has multiple stages and phases such as blow molding where preform is being either extruded or injected and transferred later to station for blowing, our mounted robotic arms streamline transfer process between two working station with efficiency and safety. With 120 injection molding presses and extrusion/injection/stretch blowing that range from 15 to 310 ton clamping force, we are able to manufacture plastic parts of all sizes and any volume.
Most of the food and medical packaging will require a clean room manufacturing environment. We have an ISO 14644-1 certificated at grade ISO 5 Class 100 clean room, which has a maximum particles of 293 under 5 micrometer per cubic meter. This allows us to manufacture and supply plastic packaging consistently for cosmetic, food and beverage, and pharmaceutical industry.
Inspection and Quality Control is very critical not only to part manufacturing but also to mold making. It can discover the defects that eventually may result in failure of the production project and therefore can fix it before a big loss. We have a fully-digitalized optical inspection system together with our gauge and measuring system to handle all the detail work to meet the product specification and control the tolerance level.
Our engineering team will assistant our customer in early stage of a new production development. Part design in CAD(Computer Aided Design) usually followed by the concept development. Our engineers are proficient in most of the mainstream modeling software such as Pro/ENGINEER, SolidWorks, and AutoCAD.
Design for Manufacturing is an important principle when it comes to plastic part manufacturing. It all focus on a goal that aiming to the most cost-effective solution from the production point of view. Our engineering team has over 10-year experience in designing plastic parts of all kinds and which give them the expertise to build on a solid system taking the most critical aspects into account which includes mold thickness, draft angles, material selection, molding cycle time and more.
A critical aspect of a cycle of the injection mold manufacturing will be the gate position and resin material flow in the mold. An inappropriate design and placement of the gates in the mold can result a significant negative impact in cycle time, cooling, packing issues, scrap rates, and surface quality. Mold flow simulation allows us to find out the potential problems in the design and figure out the optimal solutions to get the best results in our production, getting better product quality and saving money in a long run.
Prototyping is an important transitioning phase between design and mass production for any new product introduction. It allows us to prove the concept and optimize the design that eventually made ready for mass production. Thanks to our in-house tooling department, we are able to offer the three different prototyping options at our customer’s choice: 3D printing (SLS, SLA or Material Jetting), CNC machining in plastic and Low-run aluminum injection molding.
For handling all of the mold making request, our in-house CNC milling machine using rotary cutters to remove undesired material by advancing a vertical cutter into a work piece in 3+2 axis. With the numerical control program and our experience technicians, even the most complex shape can be achieved in high precision.
In addition to CNC machining, EDM is another important process in mold making. It is a manufacturing process whereby a desired shape is obtained by using electrical discharges between two electrodes. EDM can take care of the shaping of even pre-hardened steel which is not possible to CNC machining without heat treatment. Our EDM process usually will be taken after CNC machining during the mold making.
Polishing and grinding are two important methods of surface finishing treatment for injection mold making. Our grinding machine is also totally computerized numerical control, with the power of Computer-Aided Manufacturing, our grinding machine can finish any of your finish request with high precision and efficiency.
At Cannapco, the latest in 5-axis laser texturing technology combines traditional chemical mold texturing and engraving processes to meet the our customer’s demand on post-mold processing and finishing, and decorative manufacturing for branding and labeling purpose.
Quality Control is critical both in manufacturing and tooling process to achieve accurate tolerance control. Our optical inspection system complements with our fully digitalized gauge and measuring system enable us to enforce quality control, making sure product specifications and colors are strictly met at every step.
Tool maintenance is essential to ensure longevity and consistent processing performance. Here at our tooling department we employ routine preventative maintenance procedures on all molds as specified by our customer or engineering to ensure proper performance. We also handle mold repair or changing parts on a regular basis.
In terms of molding types, we are able to handle to insert molding, over molding, injection molding, and blow molding with tolerance range is up to 0.01 mm that applied for rapid molding, low-volume molding and production molding. Material-wise we use Q-7/1.2344/1.2343/2047 for aluminum mold, and in stainless steel mold 420/NAK80/S136 is used for core/cavity, while P-20/S-7/H-13 for the mold base. For the size and weight limit of the injection mold, our shot size maximum is 30 oz and the corresponding part size should not exceed 10 inches on each dimension. Multi-cavity mold is available with number of cavities up to 256.
When it comes to resin selection of plastic parts to be manufactured, we are able to offer both engineering grade resins and commodity resins. For the engineering grade resins, our offer includes Nylon, ABS, Thermoplastic elastomers (TPE), Acrylic, Polycarbonate and Structural foam. Polypropylene (PP) ,Polyethylene (PE) , Polystyrene (PS) and Polyvinyl chloride (PVC) is the choice of commodity grade that we offer. Custom addictive to the resin is made possible for special request on the product strength, conductivity, and other chemical or electrical properties. Masterbatch is also chosen carefully to meet our customer’s request on the product colors.
For labeling and branding purpose, it’s very common that our customers may ask for decorative manufacturing, mold/part surface finishing and secondary or post-mold processing such as assembly and packaging. We offer glossy finish, matte finish, textured finished and As-machined finish according to SPI standards on both mold and the parts. For the decorative part, we offer pad printing, heat transfer, laser etching for texturing, and hot stamping. Mechanical or manual assembly is also available upon request.
We are a ISO 9001:2015 certificated and complied manufacturing facility for plastic parts. Moreover, we also have an ISO 14644-1 certificated at grade ISO 5 Class 100 clean room that make us eligible for supplying packaging for food/beverage industry, cosmetic industry and pharmaceutical industry. We are also able to apply for certificates for the products that manufactured through us such as ASTM certificated, CE/UL mark, GMP and so forth.
Pad Printing transfers ink from a silicone pad onto a custom etched design while automated equipment shuttles the pad, depositing the design on the specified location. Our pad printing service creates fixtures that provide accurate impressions in custom colors to meet your branding and labeling requirements.
Thermal transfers are pre-printed images using silkscreened, gravure, flexography or digital printing methods on a release paper or film. With Cannapco, your plastic decoration project will be streamlined, simple, and cost-efficient.
Hot stamping uses a dry image created by a die using high heat. It can also be used to apply foil or embossing. The foil can be metallized to provide a wide variety of metal finishes including the most common gloss, matte or brushed chrome, silver or gold finishes.
Mold texturing, also known as engraving, is the process of adding a pattern to the molding surface of a mold, which is either accomplished by chemical etching process or laser blades that applied to the mold. Our experience in this field allow us to develop the most effective texturing processes that is tailed made to your specific project.
Whether you are looking for joining multiple parts using ultrasonic/hot plate welding, integrating machined or fabricated metal/electronic components, or final assembly of the entire product, our Assembly Team can customize the process to make your product in a form that’s ready to go to market faster.
Cannapaco is a US-based leading manufacturer in plastic and glass container who specializing in cannabis industry. We offer a wide range of product line that covers the whole spectrum of dispensary supplies, including versatile storage solutions and child resistant packaging that complies with state regulations for the safe sale and distribution of legal cannabis and personal care products.
Our premium quality packaging solutions sealing out moisture and air, safely storing cannabis products in the form of flowers, concentrates, pre-roll and edibles for our customers. Our factory direct price also help our customers to save money in all their packaging supplies.