Posted on July. 10th, 2020, | By WayKen Rapid Manufacturing
Manufacturing has undergone drastic changes in the last 10 years. Massive mass production plants are giving way to smaller facilities that have less capacity for large volumes but are capable of delivering small batches, customized parts, and prototypes in a short span of time. These facilities are called CNC machine shops and CNC prototyping shops. Let us look at why they can be more useful than conventional manufacturing plants.
What is a CNC machine shop?
A CNC machine shop is a high profile manufacturing facility that will deliver your orders if you need metal, plastic, and other parts for different machine components. Depending on the capabilities of the CNC machine shop, they can concentrate on specific industries: automotive, aerospace, medical, and so on. Some shops have hired capable design and analysis engineers and can provide you with complete engineering design, verification, and production of your idea.
CNC machine shops tend to be at the cutting edge of manufacturing technology. The market is highly competitive and the shop that can deliver high-quality CNC parts faster will survive. Let us look at what kind of equipment you can find there and how it can be useful for you.
Quick turn prototypes to full production runs
What Can You Find in a CNC Machine Shop
A fully functional machine shop usually includes many pieces of the machine equipment as bellows:
A multi-milling machine is a machine tool that can conduct a wide range of machining operations. It usually doesn’t have any Computer Numerical Control (CNC) system and is operated manually by a machinist. The main advantage of such a tool is that with a capable machinist, you can simply give him the drawing and he will start machining right away. It’s a great option if you need a single simple metal part. You can get it within a couple of days.
Machine Center ( 3,4-5 axis CNC machine)
A Machine Center is a more complex version of the multi-purpose milling machine. You will need a 3D-model of your part to get it manufactured but the advantage is that a CNC Machine Center can manufacture almost any part you can imagine. They are quite precise too, and if you like the result, you can duplicate the first prototype easily by simply loading the same NC program again and again. CNC machine centers can have 3, 4, or 5 working axes. The more axes a CNC machining center has the more complex parts it can make.
But if your part is simple, it is better to go to a multi-milling machine because the machinist will need quite a while to prepare a good NC program.
A lathe is a kind of machine tool where the part revolves instead of the cutting tool. It is perfect for symmetric components and can work on them automatically if equipped with a CNC system.
A grinding machine uses high-quality grinding wheels made of small hard particles to shave off small layers of materials and form a very precise dimension with a great or mirror-like surface finish. Such operations are used for high-precision parts and it is recommended to use them only for tolerances IT 7 or higher. They are costly and take up a lot of time.
A drill press is the basic manufacturing machine tool. It is used to drill holes in any kind of part. It serves as a good complement for multi-milling machines and manual lathes forming a perfect combination to make parts swiftly.
Every CNC machine shop needs blank stocks. 90% of those are supplied in the form of long bars of different diameters. When an order is made, the bar is cut into single pieces and a part is machined from those. A bandsaw is used to cut those bars.
Micromachining is a machining process on a microscopic level. It allows you to create microscopic finishes on a part and create custom surface finish patterns.
EDM refers to electrical discharge machining - a process that relies on electric currents to vaporize particles from the surface of the part. This method is perfect for hardened aerospace parts and dies cavities. A tremendous advantage of the process is that the cutting force is close to zero so the part cannot be deformed during its processing.
Surface Finishing Tools
When the part is complete, you sometimes need to get additional properties. Such as mirror-like surface finish, color, glossiness, or smoothness. All of them require special treatment so a good CNC machine shop usually has at least a small set of painting equipment. Great machine shops offer polishing and anodizing services.
Coordinate Measuring Machine
In order to check the tolerances of the part and evaluate its properties, control equipment is necessary. Coordinate measuring machines are the best fit for the various orders a CNC machine shop gets. They are precise and can measure virtually any dimension.
One stops post finishing
You can get your desired workpiece under a single unit within the limit of time frame; you don’t need to move shop to shop for different job operations. Detailed finishing is the main concern of machine shop on which they will never compromise.
Following are the post finishing techniques;
- Hand Finishing and Form fit function: A common aspect of model finishing is adding inserts or functional assemblies. E.g. adding a metal threaded insert allows for more durable threads when an item requires screws or bolts in the assembly process.
- Sanding and Polishing: In this process, the product defects such as, burr, machine line, and adhesive mark from the surface of the part were removed by efficient hand sanding and polishing which may take hours.
- Painting and Printing: Clean paint represents the quality of the product. Painting and printing are done in a strictly controlled environment which may be done by spray guns or airbrushes.
- UV Coating: UV coating is able to resist ultraviolet radiation and protect the material to enhance its durability and wear or scratch resistance.
- Laser Etching: Etching refers to the process of material removal and in a machine, shop etching is done on a specific area for printing brand name logo or custom message before moving to mass production.
CNC-RP Quality Control:
There is a detailed inspection steps and tools which are used for quality control process of the product being produced by CNC machine shop.
- Inspection by machine operator: It's very common for the operator to do various inspections on the part either while it is still on the machine or immediately after removing it from the machine.
- Customer Communication: Effective customer communication as an essential element of delivering customer satisfaction.
- Verification of Purchased Products: All purchased products are subjected to a visual inspection by the receiving quality control inspector.
- Inspection via in-process Probing: In-Process Probing is the buzzword for using an automated probe to check tolerances on a part as part of the part program.
- Inspection in the Quality control department: There is an additional inspection step made by the Quality Control Department according to the Statistical process control system after the part comes off the machine and leaves the operator's hands.
Quality control and quality management comprise a variety of tasks, measures, and activities that extend over the entire product life cycle for each product.
Quality control can save the day in two ways:
- You will get the desired quality of your workpiece.
- Will finish the project without undue waste.
For better quality results use high precision equipment and software.
CNC Machinists Create High-quality Precision Machined Components
Another vital element that ensures the work of a CNC machine shop is its staff. If the machine tools are the heart of the shop, machinists are its brains. A capable machinist can take a drawing and turn it into a part without any previous preparation. He can set up the machine tool and the cutters and do everything himself. A good CNC machinist will create complex programs for the CNC machine centers and provide the shop with complex and high-quality part orders.
CNC machinists make sure their machines are working at full capacity, are stocked with needed materials, well-maintained, and perform periodic checks on output. They inspect the finished product to ensure that it is defect-free and ready for the next step in production.
A professional machinist and craftsman should have the following skills;
- Problem Solving Skills: CNC machinists will need to know how to fix errors, how to increase efficiency, and why machines are not at peak performance.
- Technical knowledge: Machines controlled by computers will need operators who understand CAD/CAM technology.
- Attentive: CNC machinists will work with precision equipment. Being off by millimeters could be a critical error. Keen attention to detail is required.
- Math Skills: For understanding complex instructions the CNC machinist should have good math skills, and make sure items are designed and built correctly.
- Stamina: CNC machinists should have good stamina because they often work long hours doing repetitive movements.
Now we will discuss about the inspection tools used for quality control in machine shop.
- Coordinate measuring machine: It measures the geometry of workpiece by sensing discrete points on its surface with a probe. Various types of probes are used in CMMs, including mechanical, optical, laser, and white light.
- 3D scanner: A person moves the 3D scanner around the workpiece to capture its different parts and provide its 3D model. The process normally takes 3-4 minutes.
- Vernier Caliper: This is the most important tool which is used to measure the outer dimensions (using the main jaws), inside dimensions (using the smaller jaws at the top), and depths (using the stem) of the workpiece.
- Micrometers and Pin Gauges: If the desired workpiece is needed to be highly precise then micrometer is used for measuring depth, length and thickness. Pin gauges are used to measure and inspect the diameter of small holes in machine shops.
- Roughness tester: It is used to check the surface quality of the product. The surface roughness can be detected by the deflecting needle of the tester.
CNC machinists are specialized on one complex machine. They are builders, fabricators, mechanics, craftsmen, and quality assurance all wrapped into one.
How to Ensure Machine Shop's Safety
A machine shop is dangerous working in place. That’s why a lot of safety rules are imposed. Workers have to wear casks and special attire, special goggles to prevent chips from reaching their eyes. They have to undergo special courses in machining safety and adhere to the current rules.
Faced with those safety problems, here are some tips for optimizing your CNC machine shop and help you to make the right choice.
Are you still looking for a respected, trusted CNC machine shop? WayKen as a prototype manufacturer can provide advanced manufacturing and prototyping solutions for global customers.
Outlined above are the basics of the CNC machine shop dealing with CNC machining and prototyping, which is the fastest and precise way to produce a prototype of your desired dimensions. Various CNC tools and their equipment which are used by the machine are discussed in detail. We also discuss the professional machinist; about his abilities and requirements to be considered as a professional machinist and some of the Considerations that may be taken into account by manufacturers and CNC machine shops while producing a workpiece on CNC machine. Tools used for the purpose of quality control are also discussed above in detail.