Plastic Sports Bottle Molding Manufacturer

OEM & ODM Services: Product Design Services, Prototyping Services, Mold Design and Manufacturing Services, Injection Molding Services, Overmolding Services, Blow Molding Services, Assembly Services.
Software: UG (Unigraphics NX), 3DMAX (3D Studio Max), ProE (Pro/Engineer), AutoCAD (Autodesk Computer Aided Design), PS (Adobe Photoshop), CDR (CorelDraw).
Material: Taiwan Chemical Food Grade PP, Food Grade TPE Soft Rubber, Food Grade PET, Imported 718H Plastic Injection Mold Steel.
Quantity: More than 1.2 Million Sets.
Plastic sports bottle molding manufacturer

Plastic Sports Bottle Molding Customization

The initiator of this project is a European brand that focuses on outdoor drinking water safety. And they were trying to find a good plastic sports bottle molding factory. Before the client contacted our factory, they had tried two functional lids, but the results were far from satisfactory. Due to their previous manufacturer’s poor structural consideration of the product design, which resulted in more than half of the defective products leaking water in mass production, and squeaking when drinking, the customer decided to abandon the spout rotating style lid. The customer showed us two failed products he received earlier (pictured below).
failed lids

This project is a sports bottle that cyclists can open with one hand and drink water during riding. It consists of three parts: plastic lid, blow-moulded bottle body and filter element. Super filter paper is assembled inside the filter element. In the outdoor environment, users can put natural water into the bottle, squeeze the bottle body, let the water filter through the filter paper and drink it. This design concept is very practical and very environmentally friendly.

We understand that there are three key issues that need to be addressed. First, better sealing function than regular kettle lids. Second, additional structures need to be designed to fix the filter element. Third, it is necessary to design a gas nozzle to coordinate the internal and external pressure difference of the bottle body during the extrusion process.

After a thorough exchange of opinions with the client, this water bottle named Click Lid became the first cooperation project between us. Do you think there is a conflict between the valve structure and the more powerful water sealing function? Don’t worry, please continue to browse this case.

outdoor water bottle

Product Design for Plastic Sports Bottle Molding

Based on the customer’s description and relevant data, our product designers first drew a rough prototype and sent it to the customer for discussion. On the basis of our suggestions, the client keeps coming up with new ideas and more reasonable considerations, and finally, we provide the design drawings of the bottle lids that customers are most satisfied with. The most satisfying thing is that we designed a plastic water bottle lid with a double sealing effect, and even the structure of the air valve is a double safety design to prevent water leakage.

Our factory has 18 years of manufacturing experience in the plastic mould and injection moulding industry. We have excellent English communication skills and a good engineering understanding of plastic mold manufacturing and injection molding processes. From design to production, we communicate smoothly with customers, accurately convey opinions and suggestions, assist customers to analyze and eliminate unreasonable factors in mold manufacturing and injection molding, and complete every step proactively, objectively and accurately.

Our product designers are not only skilled in using UG, AUTOCAD, PS, and CDR software, but also have more than ten years of rich experience in mold manufacturing and injection molding. Drawing reasonable and accurate product design drawings is the premise for the smooth progress of this plastic sports bottle molding mass production.

filter plastic part of sports bottle

Prototype Manufacturing of Sports Water Bottle

Fast prototyping validates product designs. At different stages of product design, it is necessary to use 3D printing technology or CNC machining to manufacture a quick prototype to verify whether the product design is reasonable and whether it can achieve the effects and functions that customers want.

For this project, the plastic cap base was made with 3DMAX’s SLA/SLS 3D printing, and the top cover was made with CNC machining and vacuum casting. The natural color of 3D printing materials is generally white, which is not conducive to displaying the appearance of the product. Therefore, we will also do surface finishes on the plastic prototype, such as sandblasting, polishing, and oil injection.

After the prototype is manufactured, our product designers and mold engineers will discuss and come up with improvement plans, and then make a report and send it to the client. According to customer requirements, we made three prototypes in total, and finally determined the perfect design plan in the customer’s mind. In this process, every prototype has a lot of credit to help the customer find more reasonable and accurate improvement directions and solutions.

Prototyping service for plastic sports bottle molding

Mold Design for Plastic Sports Bottle Molding

After the prototype is confirmed, we can use the confirmed product design drawing as the final product drawing and put it into the steel mold manufacturing stage. Our tooling engineers work closely with customers and with product designers. This careful evaluation often reveals small details that can be modified, helping our mold engineers to make the best mold opening plan and then design the most reasonable mold drawing.

Select Mold Steel

Mold steel affects the life of the mold. The expected number of products is one million units. Considering the PP plastic material and the slider structure inside the mold, we give priority to using imported 718H mold steel with a high lifespan to manufacture the mold core. It can guarantee the normal work of the mold to reach more than one million times. Its higher hardness can also resist the deformation problem after the mold core is opened and closed many times, thereby ensuring that the bonding line on the injection-moulded product maintains a good appearance.

Determine the Number of Mold Cavities

On the premise of meeting the output, a reasonable number of molding cavities can help control the cost of the mold. The customer’s monthly product requirement is about 50,000 sets, so we recommend two cavities. The reasons are as follows:

  • 1. According to our many years of injection molding experience, its molding time is about 60S, and the daily production capacity of the 2-cavities mold is about 2500pcs, which can meet the monthly demand of customers in terms of production efficiency.
  • 2. The 4-cavities mold is more efficient, but the cost of the mold will be much higher. From the perspective of customer interests, the choice of 2-cavities is the most economical.
  • 3. The lid of the water bottle is round, and the top is the apparence surface. The glue feeding from the top will affect the appearance of the product. The design of two cavities can make the design of the side glue inlet more reasonable.
  • 4. The outer ring of the plastic bottle cap has a concave design, and it is necessary to design a slider in the mold for good demoulding. A two-cavities mold is just right for designing such a slider.
two cavities mold of plastic sports bottle lids

Determine the Location of the Injection Gate

The location of the injection gate is very important to the molding of the product. After the FDM mold flow analysis of our mold engineer, we chose the large nozzle on the side to feed the glue. Such an injection gate design is beneficial for the molten plastic to quickly fill the cavity. And the gate is designed to be hidden and can be covered by other silicone parts. This is taken into account when we design the product.
injection gate of plastic bottle lid molding

Double Thread Design

The double-threaded structure is also where this sports bottle lid is different from conventional lids.

The thread of the bottle cap is adapted to the external thread of the blow-molded bottle. When the molding result is neat, it can give the user a good experience. Therefore, we avoid forced demoulding, but use the rack to drag the pinion insert to rotate and unthread. The rack stroke and gear ratio are calculated accurately by our engineers. In order to prevent the product from rotating during the rotation of the gear insert, we designed some small slots at the bottom of the plastic cover to better fix the product on the back mold.

There is another thread in the centre of the cap. We have done a double-layer rotary de-threading mold before, and our experience tells us that the cooling system cannot be designed inside the rotating insert, which will lead to a poor cooling effect of the product during the injection molding process. So how to solve this problem? Since a cooling system is necessary, we use replaceable movable inserts to form the middle thread. Inserts are placed into the mold before each molding. When the lid is formed, remove the movable insert. Can it be forced out? No, preferably not. Because from the point of view of product function, after the filter element and the cover are assembled together, the excellent water sealing effect is still the first important thing. Otherwise, the filtering effect of the filter element will be useless.

plastic bottle lid mold design

Prevent Product Shrinkage

There are two places on the lid where the plastic is too thick. According to our injection molding experience, irregular shrinkage pits will be formed here. But here is the product appearance side. From an aesthetic point of view, we recommend preset two regular oval grooves. This is exactly the value of our ODM service. The client’s original design is generally difficult to notice these details. And our mold engineers predict problems with rich industry experience, and then implement some improvement measures to reduce the occurrence of problems and save mold manufacturing time and production costs for our client.
plastic part design

Select Hot Runner or Cold Runner

On the basis of meeting customer needs and product quality requirements, we recommend that customers use cold runners. This not only saves tooling investment but also shortens tooling time.

Draw Mold Diagram

After completing the most important DFM analysis and improvement, we can start the mold drawing work. Our mold design engineers usually use UG (Unigraphics NX) software for 3D modeling of the entire mold. This software is highly valued in the mold design industry. UG can easily and quickly help us design a clear three-dimensional mold file.

In this plastic water bottle mold, a very important point is the design of the rotatable mold inserts and the prediction of the motion state after assembly. The oil cylinder drives the rack to do branch line movement, and then the rack drives the gears at all levels to rotate, and finally realizes the rotation and backward movement of the inner thread insert. This puts forward higher requirements for mold design engineers. There can be many small inserts that cooperate with each other inside the boxy mold shape.

plastic bottle lid mold
The mold design work is not over yet. Our mold engineers need to break down the 3D drawings into 2D files that can be processed for production. At this time, AutoCAD software is needed, which can quickly and accurately output two-dimensional drawings of mold parts.
Regarding the tolerance setting of mold parts, it is necessary to meet the purpose of reasonable assembly of mold parts. For example, the hole cannot be set to a negative tolerance, otherwise, the insert cannot be assembled smoothly. The negative tolerance of the slider size should not be too large, otherwise, the gap at the joint position of the slider will be too large, and the PP plastic material in the molten state is prone to drape during molding. Therefore, the mold design work not only requires a very efficient drawing ability but also requires the mold design engineer’s experience in mold manufacturing and plastic injection molding.
mold 2D drawings

Steel Mold for Plastic Sports Bottle Molding

According to the 2D drawings, our mold technicians will be responsible for mold manufacturing management and mold assembly and fitting.

Mold manufacturing is generally divided into the following 5 steps:

  • 1. Customized LKM mold base reprocessing, including CNC machining, drilling to manufacture water cooling/oil heating systems, wire cutting of insert holes and thimble holes, etc.
  • 2. Process the mold core, including wire cutting, drilling, CNC machining and EDM machining, etc.
  • 3. Process mold parts, including CNC turning, CNC milling, Sodick wire cutting, precision grinding, milling, EDM processing, etc., and mark each part with laser marking.
  • 4. Procurement and reprocessing of standard mold parts.
  • 5. Mold assembly and adaptation work.

Quality control at every step of mold making is important. The most important thing is the final mold assembly and adaptation. Assembling the finished mold parts one by one requires not only accurate cooperation between them, but also smooth mutual movement between them, so as to ensure that the mold can work stably during the injection molding process.

mold building service

Plastic Sports Bottle Molding Process

After the mold assembly is completed, T0 mold trial and trial injection molding are required. The purpose is to check whether the opening and closing process of the mold is smooth, whether the mutual movement between the mold core inserts is smooth, and whether the movement of the ejector structure is consistent with the design. During the mold trial stage, our injection molding technicians, mold manufacturing technicians, and mold design engineers for the mold all need to be on the production site.

Prepare PP plastic raw materials and toner/masterbatch according to Pantone color code requirements. After the mold runs smoothly, the injection molding technician adjusts the molding conditions of the injection molding machine for trial injection. The injection temperature needs to be selected according to the characteristics of PP plastic raw materials. Injection pressure needs to be tried gradually in order from low to high. Injection molding time and cooling time also need to be adjusted according to the appearance of the plastic product tested each time. After many adjustments and trials, we got the perfect plastic sample. At this time, record these molding conditions and make a trial report.

After the customer confirms the trial sample, we carry out mass production according to the injection molding conditions of this Golden Sample. The SOP document must be learned and properly understood and implemented by employees during the training session. IPQC’s inspection work is also not to be ignored. With everyone’s joint efforts, we can control the quality of batch products.

Plastic sports bottle molding factory

Blow Molding of Water Bottle Body

On the basis of good communication with customers, we also assist customers to design the bottle model. Blow molding is a process that belongs to thermoplastic molding. For the unified management of the entire project and to ensure the stable quality of each link, we provide customers with contract manufacturing services to assist in the blow molding process of this bottle.

Based on our quality control concept for plastic products, our client trusts us to entrust the quality control of this blow molding product to us. At the same time, they also save communication time and cost control corresponding to multiple suppliers. This is also the value embodiment of our one-stop service for our customers.

Plastic sports bottle molding manufacturer

Product Assembly, Packaging Customization and Shipping Services

Our assembly department is equipped with assembly lines and equipment required for assembly, such as plastic ultrasonic welding machines, silk screen printing machines, pad printing machines, special electronic testers, etc. Cooperative packaging and printing factories can help us customize product packaging and pattern printing required by customers. Our assembly department staff will complete the assembly and packaging work in an orderly manner according to the SOP documents, and then seal the box and send it to the finished product warehouse, waiting for the customer’s shipment arrangement.

This series of work can be done under our control. The customers only need to explain their ideas and requirements to us, instead of dealing with all kinds of cumbersome affairs with three or four suppliers. It can avoid the cooperation problem of all parties and the conflict between different production plans. This is also the core value of our one-stop ODM service for our customers. We focus not only on high-quality products but also on high-quality customer service.

Your One-stop Manufacturer for Customization

Sungplastic is a leading provider of on-demand manufacturing services in China. Precision plastic tooling and injection molding are our core, while prototyping and CNC machining can better support the needs of low volume production. We provide plastic injection molding and contract manufacturing in home appliances, consumer goods, electronics, LED lenses, industrial products, automotive, and energy markets.

When you choose Sungplastic , you get a professional partner through the entire production cycle. Timely, professional, and effective communication is always with you, taking your product from concept or drawing to reality.

We hope you enjoyed this plastic water bottle case study overview and may have gained some ideas and insights to help you with your next project. Do you have a great idea that you also want to make a reality? When you send an RFQ today and upload your CAD files to sungplastic.com, we’re always ready to provide a free quote and project research.

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