Plastic CNC Machining is a computerized control process that typically entails subtracting material from a solid plastic block. Generally, it’s done using a
cutting tool commanded by an electronic file. To get the required shape the
machine only moves along the pre-defined patterns. CNC machining is an accurate
and fast process of manufacturing plastic parts. However, effective machining
depends on the material used and the proper technique that is to be applied to the
material.
What Is Plastic CNC Machining?
Plastic CNC Machining
Plastic CNC machining is a process by which Computer Numerical Control (CNC)
technology is applied in the manufacturing of parts from various plastics. In this
process, computer programming controls the motion as well as the operation of the
machine tools, and thus, quality is achieved. CNC machines are versatile in that they
can be used to cut, drill, and shape plastics to produce both basic and sophisticated
parts. Even though CNC machining can be used on all materials including metals,
ceramics, and woods, this term is specific to the use of the technology in plastic
machining. The process is most commonly used in industries that demand high
accuracy, for example, the medical sector, automobile industry, and the electronics
industry.
Can Plastics Be CNC Machined Precisely?
Undoubtedly, yes, plastics In fact, plastics can be CNC machined to high degrees of
precision and productivity. CNC machining is one of the most suitable processes for
producing plastic components particularly because it provides accurate and
repeatable results. This process is useful particularly when compared to other
methods like injection molding or 3D printing, using CNC machining delivers a
product with the same precision at a much faster rate. The versatility is also
enhanced by the ability to machine plastics of varying plasticity ranging from soft to
high performance. CNC machining is commonly used for making prototypes, special
parts, or intricate plastic parts.
Common Plastics for CNC Machining
Thermoplastics are the most frequently used materials in CNC machining among all
materials. They can be reused in the molten state and still retain their
characteristics. Depending on the nature of the job in question, different forms of
thermoplastics may be useful depending on the properties in question. Selecting the
correct plastic material is very important since there are different plastics in the
market and their performance levels vary. Some of the most commonly machined
plastics are described below in this passage.
Nylon or Polyamide
Polyamide CNC Machined Parts
Nylon is highly appreciated for its thermal and chemical stability. This material is
very stable and thus very easy to machine this material is sometimes compared to
metals such as brass. The kind of CNC tools that are suitable for nylon are those
made from tungsten carbide because of the characteristics of nylon. In terms of
mechanical strength nylon is usually used in various applications. This makes be
ideal to use in the CNC machining industry due to its ability to resist wear as well as
abrasion.
Delrin or POM
Delrin Machined Part
Delrin is well acclaimed for its stiffness and its performance when placed under
stress. It is heat resistant, but it cannot withstand high heat temperatures. It
therefore makes Delrin ideal for use when designing parts that require a high
degree of strength. Delrin can be machined using CNC very easily, but the problem
arises while dealing with the structural stability of the material as it tends to expand
and contract with heat. It is usually applied in mechanical and automotive products
since they are strong and hard-wearing.
Acrylic
Acrylylic CNC Machining
Acrylic is a relatively light material but it possesses good tensile strength and high
stiffness. Due to its high wear resistance and good machinability, it is used mostly in
applications that require accurate Computer Numerical Control operations. Just to
note a smooth surface finish depends on the sharpness of carbide cutting tools.
Sometimes, acrylic is selected for uses where transparency or lightweight and high
strength are desired. Tooling and settings should be well chosen to prevent tool
breakage and other forms of damage while machining.
PEEK
PEEK CNC Machined Parts
A material – PEEK (Polyether ether ketone) is a famous high-performance plastic
with a high melting point. It has better mechanical properties to be used in CNC
machining. PEEK is applied in industries that call for high dimensional accuracy
including the aerospace and medical industries. However, some processing of this
material such as machining causes it to break due to some internal stresses. The
reason for its preference in demanding applications is because of its accuracy and
ability to withstand high heat.
PTFE
PTFE Machined Components
PTFE is also known as Teflon and is immune from chemical, heat, and electrical
impacts. It has a high tensile strength, which makes it ideal for CNC machining;
however, tight tolerance requires high levels of precision due to a high coefficient of
friction. It has its stress properties regarding which special machining techniques
are needed. PTFE is used in industries that require, a high temperature of working,
for example in the production of electrical parts. Proper tool choice and how a
machinist handles the tool is very important in the process of machining.
UHMW
UHMW CNC Machining
UHMW (Ultra-high molecular weight polyethylene) belongs to the family of
thermoplastics, typically has high tensile strength, and does not corrode easily.
Machining of UHMW is challenging because of the material’s inherent instability, but
it is still the material of choice in prototyping. Choosing CNC machining over
molding is attributed to material properties for this type of application. For these
reasons, it is wise to deal with specialists who deal with UHMW since it is not easy to
machine. Some of the industries that apply this material include the automotive
industry and food processing industry.
How plastics are CNC Machined Precisely?
CNC milling comprises the material is cut by a rotating cutter. Machines can be as
complex as to have three or more axes of motion to deal with more complicated
geometries. The three-axis is used for basic designs while the multi-axis is used in
designs that require more details. When it comes to thermoplastics joined with glass
or carbon fiber, carbon-based tools are used. Applying clamps also enables one to
attain higher spindle speeds, as the results show.
Plastic CNC Turning
Plastic CNC turning entails fastening a plastic part on a lathe and then turning it
against a cutting tool to produce the required shape. Straight or cylindrical turning
is applied for making big turning, while taper turning is applied for making cone
turning. The following machining parameters are necessary for successful turning,
for instance, adequate cutting edges should have a negative back rake to minimize
rubbing. Also, large relief angles and polished surfaces are preferred to avoid
collection of material and better finish on the surface. Using C-2 grade carbide
inserts fine enables high precision and long-lasting cutting edge on the work
surface.
CNC Plastic Drilling
CNC plastic drilling is the process whereby drill bits are used to make holes in the
plastic blocks and the CNC drill presses include radial, upright, or bench kinds. The
drill bits that are used in excellent working condition and
unblemished to prevent the marring of plastic parts. For most of the thermoplastics, the
lip angle should be between 9 to 15 degrees while the drill range should be between
90 to 118 degrees. Acrylic for instance needs a 0-degree rake angle when it is being
drilled. To avoid overheating and potential damage to the materials it is necessary
to control the chips’ removal and to decrease the feed rate when the drill is near the
end of the hole.
Improving Surface Finish with Additional Treatments
Perfectly?
The surface finish of plastic material in CNC machining can only be done with
particular techniques that are appropriate to the characteristics of the material. To
avoid different kinds of poor finishes, the cutting tools should have simple
geometries, and the right feed rates should be employed. The clamping of the plastic
material should be well done to avoid vibrations that might cause surface roughness
of the final product. Also, the cutting speed has to be changed depending on the
type of plastic as well as to avoid any negative results. Other surface treatments,
such as annealing, sandblasting, and powder coating may be applied to improve the
surface roughness and appearance of the plastic parts.
Mistakes to be Avoided in CNC Machining Plastics
However, some issues with plastic CNC machining cannot be fully controlled no
matter how much one tries and it is good to be informed of the challenges.
Misshapen, incomplete, or damaged prototypes are common when the knife speed
is set wrong with the plastic material. Trial runs should be done whenever working
with plastics and preferably with different batches of the material. The type of tools
is another important factor; using metallic tools to work on plastics will lead to tool
breakage because of the difference in hardness between the two materials say
nylon and metal. Also, what can go wrong is that the two processes need to be
gradual with a roughing-out process being followed by a finishing process as this
reduces defects and increases quality.
Why do People Prefer CNC Machining over Other
Conventional Methods?
CNC plastic machining is a widely used process for making plastic parts because it
offers certain advantages over other forms of rapid tooling such as injection
molding and 3D printing. One of them is its precision and accuracy. CNC machining
provides a high level of accuracy, so one can achieve high repeatability and use
interchangeable parts made of plastics. Besides, it is quite appropriate for creating
intricate patterns. However, there is some truth in this statement because 3D
printing also can create designs with high levels of detail; nevertheless, accuracy
makes CNC machining better. It also boasts of producing thin walls and small
features which is a plus in many industries such as the medical and automotive
ones. In addition, CNC plastic machining works with a wider range of plastic
polymers, including robust materials, and is thus capable of being used in a wide
variety of applications.
Applications of CNC Machined Plastic Parts?
CNC plastic machining is popular in a range of industries because plastic polymers
can have a range of properties depending on their composition. Some common
applications include:
● Creating general industrial products, as well as automotive and aerospace
parts because of the high accuracy needed in the healthcare sector.
● Manufacturing of plastic components for the food and beverages industry
where cleanliness and precision are paramount.
● Design of insulation parts for electrical appliances to meet safety and
efficiency requirements.
● Fabrication of lightweight but strong components for automotive and
aerospace industries.
● Optical devices and lens manufacturing where acrylic has the best physical
and optical characteristics.
These applications demonstrate how CNC plastic machining can be applied with
flexibility and accuracy across all fields.
Conclusion
Polymers are widely used plastics that are applied when developing numerous
industrial and everyday-use items. CNC plastic machining has become widely
demanded due to the opportunities of high accuracy, small tolerances, and the
ability to work with different kinds of plastic. For these reasons, it is the number one
option for many manufacturers that need strong and high-quality plastic
components. From manufacturing intricate parts for medical, automotive, or
electronics uses, firms are assured of quality and precise services from CNC
machining for their needs.
Feitai Plastic CNC Machining Services
Shenzhen Feitai is a company that offers CNC machining services for creating
high-quality plastic parts. As a company specializing in CNC plastic machining
services, they provide professional services for industries that need accurate plastic
parts. Shenzhen Feitai provides customers with affordable services and after
analyzing the design through DfM (Design for Manufacturability) feedback. For the
highest quality plastic CNC machining services, you should contact Shenzhen Feitai
for your projects to be accomplished with high precision and efficiency. Contact us
now for more information and get an instant quote.
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