Dwustrzałowe formowanie wtryskowe do precyzyjnej produkcji trymerów do włosów

Trimmers are important tools for hair grooming. Interestingly, most manufacturers are stuck when it comes to deciding whether to produce a hair clipper vs trimmer. While the two look alike, a clipper has larger blades and is ideal for cutting a large amount of hair.

A hair trimmer, on the other hand, is specialized for cutting hair very close to the skin. They have finer blades and are lightweight, which makes them ideal for outlining, detailing, edging, and styling of hair. Hair trimmer manufacturers mostly make these products for cleaning the necklines, sideburns, or grooming facial hair. The main features of hair trimmers include:

• Higher precision and details: Comes with finer blades that enable sharp, clean lines.
• Cut deeper: They cut shorter than clippers, which makes them the perfect choice for stubble, detailing, and creating clean fades.
• Lighter than clippers: They are designed to be more compact and lighter, which makes them easier to handle and use for intricate detailing.

Crucial Parts of a Hair Trimmer

For startups that want to go into hair trimmer manufacturing, it is important to know the parts of a hair trimmer. Hair trimmers are made up of a detachable set of blades driven by a motor. The electronic components are housed in a plastic casing with a power switch. Below are the key components of a hair trimmer.

• Blades: This is the part that does the actual cutting. It consists of the stationary blade that acts as a comb and the moving blade that acts as the cutter. The moving blades vibrate against each other to cut hair.
• Motor: It provides the power that drives the movement of the blades.
• Housing: The body is the outer shell that protects the internal components from damage from impacts and environmental elements.
• Guards/limit combs: These are snap-on plastics that determine the length of hair that the trimmer will cut. The lengths can range from very short to long.
• Power button: Used to turn the device on/off
• Drive Link: This is the mechanism that translates the energy from the motor into blade oscillation.

Wymagania klienta

A hair trimmer manufacturer approached First Mold for assistance with two-shot precision injection mold production. According to the customer, they were building a hair trimmer mass production factory and were looking for a company that would assist with mold production. During their search for a hair trimmer mass production factory in China, First Mold came up frequently.

Before sitting for a discussion on their upcoming project, they requested a tour of First Mold’s factory and technological facility. Convinced by what they saw, they laid out the blueprint of their upcoming project. While the majority of hair trimmer manufacturers focus on adult products, this client wanted to create a product designed for children.

Since this client was new to the industry, they also wanted advice concerning the best material and injection molding process for building the different components of the hair trimmer, particularly the guards and housing. Other key requirements for the hair trimmer include:

• Grubość ścianki: 1.0mm or less
• Overall product weight: 200g to 250g
• Fault tolerance: No flash or burrs
• Obróbka powierzchni: Silk printing
• Assembly tolerance: ±0.05mm
• Mass production yield rate: ≥98%

Challenges and Solution

Since the hair trimmer manufacturer was creating a product specifically designed for children, it was extremely important that the guards and housing were without flash or burrs because of the sensitive nature of children’s skin. The reason is that burrs can leave tiny cuts on children’s skin. Also, the client wanted to create a lightweight product. Therefore, it was important for First Mold engineers to design for lightweighting.

Material Compatibility for 2K Molding

The second challenge that First Mold had to overcome in collaboration with the hair trimmer manufacturer was ensuring material compatibility. Since the production technique is two-shot injection molding (or 2K molding), it was important to ensure the two materials that will be used for the molding are chemically compatible to ensure proper bonding.

The first material must withstand the temperature of the second, hotter material during injection over it without deforming or melting. If the materials don’t bond properly, the soft-touch grip may peel off during use. Also, if the wskaźniki skurczu of the rigid and soft materials differ significantly, warping or cracking may occur.

Intricate Hair Trimmer Mold Design

The mold design for two-shot injection molding usually requires 30% to 50% more complex tooling. For example, the mold must be designed to allow the first shot to rotate to the second cavity for overmolding. It was necessary to create a mold with uniform wall thickness to ensure consistent cooling.

To achieve consistent cooling, First Mold engineers designed advanced cooling channels in the mold. This is also crucial for dimensional stability. CAD simulation also helped First Mold engineers with gate placement, analyze mold flow, and find potential warpage before production.

Hair Trimmer Manufacturing Challenges With 2K Molding

Two-shot injection molding usually requires a longer cycle time because of the extra injection steps, transfer, and cooling that happen within the machine. Also, defects are usually more common, especially in the area where the second shot meets the first. This defect can lead to flashing, curling, or peeling.

The first shot gate can leave marks. However, First Mold engineers ensured the mold design was carefully done such that the second shot covered any marks left by the shot gate of the first. This design consideration also eliminated the need for costly post-production processing and assembly delays, which would cost the manufacturer money.

Designing Hair Trimmer Housing for Lightweight

To meet the weight limit set by the hair trimmer manufacturer, every component had to be designed with lightweight in mind. For example, instead of thick walls for the housing, First Mold engineers opted for rib-reinforced thin walls.

To ensure maximum strength, the rib geometry was designed using CAD software (SolidWorks). Moldflow was used to validate the design for manufacturability to ensure uniform thickness and prevent filling issues.

Preventing Flash or Burrs in Trimmer Guard

Several steps were taken to prevent the formation of flash. The first was process optimization. This included the optimization of injection pressure and speed. Excessive pressure can force the molten material into the parting lines. Also, the melting temperature was optimized to increase viscosity for materials that are too fluid.

During the hair trimmer housing mold design, First Mold engineers increased the clamping force to hold the mold tightly closed against the internal pressure of the plastic. The machine platens were parallel and properly aligned to avoid uneven clamping pressure.

The combination of these techniques eliminated the formation of flash and saved the hair trimmer manufacturer valuable resources that would have been spent on post-production processing. Additionally, it made their product safe for use among the target audience.

Creating Tight Tolerance for Easy Assembly

Bearing in mind the tight tolerance (±0.05mm) required by the manufacturer, First Mold engineers had to use a combination of precise CAD design and CNC machining to create the hair trimmer molds. Tight tolerance is critical for ensuring components function accurately. A minor deviation can lead to assembly failure, premature breakage, or weak connections.

A tight tolerance ensures that the male hook and the female recess align perfectly every time. This prevents a situation where the snap-fit is too loose, leading to rattling of parts. It also prevents a situation where the snap-fit is too tight, resulting in excessive assembly force that could lead to component damage.

What the Client Gained by Embracing First Mold’s Solutions

When the client walked into First Mold’s facility, they weren’t very clear about the difference between a hair clipper vs trimmer. Also, they wanted to use one type of plastic for all the different plastic parts.

However, after communicating with the First Mold team of dedicated engineers with decades of experience in the field, they discovered that it was not a favorable idea. Instead, different plastic materials (ABS, PC, POM, PC+ABS, and TPU) were outlined for different components for the best results.

Although the creation of two-shot injection molding requires more technical skills, the hair trimmer manufacturer had their 2K mold delivered ahead of the planned commencement of mass production. The timely delivery allowed the manufacturer to fulfil preorders and meet the demand target.

The use of virtual simulation software allowed First Mold to limit formowanie próbne attempts to a maximum of three times. This was especially important because repeated attempts are time-consuming and costly. A combination of faster tooling and lower trial molding attempts ensured the entire hair trimmer manufacturing process stayed within budget.

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