Basics: What are CNC Machining Services and Injection Molding?
Experts predict that the global CNC machines market will skyrocket to $100 billion by 2025.
Manufacturers seeking to reduce their operating costs, workforce requirements, and component errors take a closer look at this technology and its applications.
They’re also learning more about injection molding, heralded for its ability to make the plastic parts manufacturing process reliable and efficient.
Today, we’re delving into the core of CNC machining services, alongside injection molding. Here, we’ll explain what each process involves, why it’s essential and the cutting-edge solutions changing the game.
Ready to learn more? Let’s get started.
What Are CNC Machining Services?
In short, CNC machining is an advanced manufacturing process that utilizes pre-programmed computer software to control how and where factory machines move. The acronym stands for Computer Numerical Control.
This quickens the cutting process. It also enables even the most complicated three-dimensional tasks to be completed by only a single set of computer prompts.
From milling and laser machines to grinders, routers, lathes, and welders, CNC machining can accommodate various tools.
How Do They Compare to Manual Controls?
CNC machines supersede manual controls in that they’re exponentially quicker. Traditionally, live operators were required to use various tools, including levers, wheels, and buttons, to prompt machining tools and guide them along.
This process is time-consuming and labor-intensive. It’s also susceptible to human error and, in turn, can pose a risk to the operators themselves.
Enter CNC machining services.
Let’s review more in-depth how the process works and the critical steps to know.
How Does CNC Machining Work?
Upon system activation, a developer will program-specific cuts into the software depending on the result desired.
From there, the system will dictate those commands to the machinery in use. In this way, CNC machining is one form of robotics driven by machine learning.
What’s Behind Operation?
CNC machines operate via a numerical control system. The language behind the code is referred to as G-Code.
Programmers can write and edit the code to control an accompanying machine’s speed, coordination, and feed rate. They will begin with a 2D or 3D CAD drawing, then translate it into computer code for CNC program execution.
Numerically-controlled machines have programs inputted by punch cards. Conversely, in CNC machining, programmers use small keyboards to feed the program into computers. From there, the programming remains in that computer’s memory. Operators will conduct trial runs of every program to ensure against coding errors.
The best part? Programmers can revise the code indefinitely, adding newer prompts to pre-existing ones as necessary. This makes the solution both non-static and flexible.
Once speed and function are programmed and set, manual operators can release control to the machines. Then, they can run them in predictive or repetitive cycles for as long as necessary.
Almost non-existent errors often occur when a machine is programmed to cut in more than one direction simultaneously.
This improvement in efficiency, speed, and accuracy makes CNC machinery a hot topic in the manufacturing world. Specifically, those in the metal and plastic production niches are reaping their benefits.
Open-Loop vs. Closed-Loop Systems
In most cases, especially in industrial metalwork applications, CNC machines will operate via a closed-loop system. This means the controller receives feedback from the system and can make corrections to velocity and position.
On the other hand, an open-loop system operates with a one-direction signal between the controller and the motor. This makes feedback and correction more difficult.
In instances where speed and force are more minimal, open-loop control may be permissible. More often, however, closed-loop systems are preferred for the accuracy and consistency they provide.
Most CNC machines direct movement across an X-axis and a Y-axis. Stepper motors or servo motors are responsible for positioning and gliding the tool. From there, the tool creates the exact movement dictated by the G-code.
The Advantage of CNC Machine Automation
Today, CNC protocols enable a parts production process that is mainly automated. Programmers set specific part dimensions via the CAD software, which interacts with Computer-Aided Sofware, or CAM, to produce the finished product.
Depending on the piece required, multiple tools could be used, including cutters and drillers. To this end, most modern machines are capable of performing numerous functions within a single cell.
Other systems might rely on a more complex setup consisting of several disparate machines and robotic hands that handle the parts transfer process. Even in the case of the latter, a single program still controls everything.
Both methods enable a consistent and accurate parts manufacturing process that is next to impossible to replicate manually.
CNC Machinery Types
Numerical control machines aren’t entirely new. They first arrived on the scene in the 1940s and 1950s. In that era, the machines used motors to help control the operation of pre-existing tools.
Since then, technology has improved and advanced alongside analog computers. Now, the recent advent of digital computing has given rise to the modern CNC machine.
Today, most CNC machinery is entirely electronic. Its applications range from ultrasonic welding to laser cutting and related jobs. Some of the most common types of CNC machines include:
- Lathes
- Mills
- Electric-Discharge Machines (EDMs)
- Plasma Cutters
- CNC Mills
- Water Jet Cutters
All of these tools are capable of producing a highly technical design within minutes. This includes complicated cuts featuring multiple angles and levels. Given that programmers enter the code correctly, the machine will work by the software.
An Intro to Injection Molding
When plastic parts are required to be produced in large volumes, injection molding takes center stage. It saves time and energy while reducing waste and improving accuracy.
It’s a process most commonly used in mass-production facilities where the exact part is replicated thousands or sometimes millions of times back-to-back. In these cases, each piece must look and function identically to the next.
There is a wide range of applications for injection molding, from children’s toys to cell phone cases and automotive parts.
How Does Injection Molding Work?
There are three main components of injection molding machines. These include the:
- Feed Hopper
- Screw
- Heated Barrel
First, the hopper feeds the plastic pieces for each part into the barrel. Usually, these pieces are either in a powdered or granular form. As the plastic enters the barrel, the reciprocating screw and heater bands create friction, which melts the material.
The machine then uses a nozzle to inject the molten plastic into a prepared steel or aluminum mold. Before they’re ready for the molten plastic, a hydraulically-powered mechanism clamps the molds together.
The amount of plastic inserted into each half of the mold is called the “shot.” The machine operator will calculate injection times by considering the injection pressure, shot volume variables, and the machine’s injection power.
Once in the mold, the melted plastic begins to cool and solidify, forming the cavity’s shape. This rapid cooling process can cause some shrinkage to occur. The packing process often allows excess plastic to enter the mold to accommodate this change in size. This ensures the final product is not compromised.
Once the hardening process is complete, ejector pins and a mold releasing agent remove the plastic piece from the mold. Operators will consider dry cycles to time this process precisely.
From there, the molds clamp shut again. Finally, they return to the part of the machine where they’ll be injected with new plastic.
Injection Molding Machine Types
Depending on the manufacturing scale, injection molding machines can accommodate five tons to 6,000 tons of clamping force. Machine size and tonnage go up simultaneously.
To this end, you’ll find that these machines are classified not by their size. Instead, their clamping pressure or tonnage defines them. For instance, one that can deliver 150 tons of clamping force is rated for 150 tons.
Why is the amount of pressure so significant?
It’s what keeps the mold closed during the plastic cooling process. If the pressure is too heavy or not heavy enough, it can lessen the part’s quality. It can also result in flashing, which is noticeable by excess material alongside the part’s edge.
It’s also important to know the pressure capacity of your machine to understand how it will interact with the viscosity of the plastic. The ease of flow for thermoplastic materials is measured via a Melt Flow Index or MFI. The higher the MFI, the greater the machine tonnage should be.
Also, different machines will have varying shot sizes and mold dimensions. Depending on the application, operators will need to select one that fits their unique manufacturing needs.
Meeting CNC Machinery and Injection Molding Needs
Technology continues to redefine what’s possible in the realm of traditional manufacturing. Leaders in this space are eager to put today’s most sophisticated new machines to work.
Yet, purchasing one for your operation may not be economically or logistically feasible. That’s where we come in.
We offer a range of solutions, including CNC machining services and injection molding, to help your business create the high-precision components necessary to fulfill your mission.
Contact us today to learn more about how we can transform your manufacturing process, one part at a time.
