Manufacturers lived by this rule in the early days of CNC machining. In fact, CNC machine maintenance was purely reactive, and manufacturers were fine with using their machines till they broke down. However, everything changed after downtimes started getting longer, resulting in losses worth thousands of dollars.
Today, top-tier manufacturers implement preventive maintenance practices to mitigate these challenges and avoid unplanned downtime or operational inefficiencies. This article will cover some of the best preventive maintenance practices you should carry out to get the most out of your CNC machines.
What is Preventive Maintenance?
As the name suggests, preventive maintenance is a type of maintenance that you perform on a machine to prevent accidents or failures from occurring. These routine maintenance activities ensure that your machines work the way you intend them to work.
For example, a typical preventive maintenance routine for a CNC machine would be to clean the machine, remove chips or metal fragments from the chip pan, and apply grease to dry spots.
You’re probably familiar with these preventive maintenance routines. However, there’s more to CNC machine maintenance than meets the eye. For instance, some preventive maintenance routines are best performed daily, while others could be monthly, bi-annually, or annually.
Let’s dig deep into some of the ideal preventive maintenance schedules for CNC machines.
CNC Machine Maintenance: Daily Activities
Here is a list of daily maintenance activities you (or your machine operator) must perform on the CNC machine.
Check the lube and hydraulic oil level. CNC machine manufacturers typically specify the adequate fluid level that allows desirable machine performance. If you notice that your machine suddenly starts consuming fluid excessively, it might be an early sign of other problems.
Check the hydraulic fluid pressure. We recommend a hydraulic pressure of 4.5 MPa for CNC machines.
Clean the machine. Wipe down all the surfaces of the machine to remove shop grime and metal chips resulting from cutting operations. We recommend using rubbing alcohol, rags, brushes (of varying sizes), and metal polish to clean your machines.
Apply grease to dry spots. You want to check all moving parts for dry spots and apply grease to these spots.
These activities might look quite simple (and they are). However, small oversights can pile up, causing more serious problems in the long run. Therefore, we recommend performing these checks at the end of each shift (or workday).
CNC Machine Maintenance: Monthly
Unlike the regular daily maintenance activities, we recommend that you have more intensive check-ups and maintenance activities performed by professional engineers (or specialists). These engineers are typically approved by your CNC machine distributor (or manufacturer). And they typically will perform the following maintenance activities:
Remove metal chips and apply grease to the chain on the chip conveyor.
Clean the filters on the coolant tank.
Check and remove debris from the vertical machining center’s pallet changer and receiver areas.
CNC Machine Maintenance: Bi-annually
The CNC machine specialists and engineers must perform the following maintenance activities every six months.
Clean the coolant tank. Remove any oil, sludge, or chips resulting from manufacturing operations.
Drain and refill hydraulic oil. CNC manufacturers typically recommend that you drain (and refill) hydraulic oils every six months (or after 1000 operating hours). After you drain the tank, change the line and suction filter before refilling the tank with fresh hydraulic oil.
Clean the radiator and ensure that the radiator fins are straight.
Remove and clean the chuck—the part of CNC lathes that hold and rotate workpieces.
Remove contaminants in the spindle and spindle drivetrain that may otherwise affect the overall life of the spindle. Also, ensure that the spindle belts satisfy the manufacturer’s tension requirements to avoid compromising your parts during cutting operations.
Check the alignment of the machine’s plane by performing a ballbar test—which monitors the spindle movement as it follows a programmed circular path.
CNC Machine Maintenance: Annually
Once every year, you should contact your CNC machine manufacturer (or distributor) to perform the following checks:
Remove and check the chuck cylinder for runout—which occurs when your chuck does not rotate in line with the main axis, causing inaccuracies during cutting operations.
Run a backlash program to check for backlash in the machining axis. Backlash occurs when the moving parts on your machining axes do not engage with a sufficiently tight fit to one another.
Check the CNC machine’s headstock and tailstock for tapering.
Check the turrets for parallelism and inclination to avoid jams, hang-ups, and indexing issues.
CNC Machining Services: Gensun Can Help
Now that you understand how CNC machining maintenance works, you’d agree that a proper preventive maintenance plan keeps machines running efficiently and ensures high-quality machined parts.
Gensun Precision Machining is a leading provider of CNC machining services across Asia. Not only do we have state-of-the-art CNC machines, but we also have expert machinists and engineers who implement our extensive preventive maintenance plan. This keeps our machines running efficiently at all times, ensuring you get your product done right and on time.
Computer numerical control (CNC) machinesㅡwhich utilize a rotating cylindrical tool to create cuts in a workpiece autonomouslyㅡhave completely revolutionized the manufacturing industry. This manufacturing technology eliminates the human error common in conventional manufacturing technologies. It also offers greater accuracy and precision and higher production speed.
But when manufacturing with CNC machines, you don’t just start cutting workpieces right away. Product designers must first design their model on computer-aided-design (CAD) software. And to create an accurate and efficient 3D CAD design for CNC machines, you need to know some essential CNC CAD design tips.
This article presents helpful tips for CNC CAD design. We will cover some design rules for creating cavities, internal edges, holes, text, and walls. We will also explain the process of preparing 3D designs for CNC milling.
5 Rules for CNC CAD Design
The CNC machining process is subtractiveㅡit removes portions of material from a workpiece to form the desired product. This subtractive nature causes some restrictions in the type of features you can machine.
For instance, it’s almost always impossible to machine surfaces inaccessible by the cutting tool. And even after you find specialty cutting tools capable of accessing these surfaces, you probably will still face the challenge of achieving desirable wall thickness and cavity sizes. However, you can prevent these challenges by adhering to the following tips during the computer-aided drawing phase of your product development process.
#1 Designing Cavities
End Mill Tool
End mill tools (used in CNC milling cavities) typically have a cutting length of about 3-4 times their diameter. As such, we recommend that you design cavity depth to be at most four times the cavity width. This helps to prevent inaccuracies in machining caused by tool deflection and vibration.
However, if the functionality of your design requires larger depth, you might want to consider using specialized tooling to create your cavities.
Because of CNC machines’ subtractive nature, they create rounded corners (or fillets) between the internal edges of a cavity. Product designers account for these rounded corners by including an internal corner radius dimension in every internal edge in their CAD drawing.
The internal corner radius dimension depends on the size of available end mill tools that meets the cavity depth requirement we mentioned earlier. Additionally, we recommend that you design your internal corner radius to be at least one-third of the cavity depth.
However, suppose the functionality of your design requires smaller internal corner radii (or a sharp 90° angle). In that case, we recommend that you include a T-bone undercut instead of reducing the corner radius in your CAD model.
#3 Designing Holes
CNC machine shops typically create holes using drill bits. These drill bits come in standard sizes (or diameters), ranging from 0.5 mm to 38 mm. We recommend that you design your holes to have a dimension similar to any of the standard drill bit sizes. This eliminates the need for additional tooling, leading to lesser manufacturing costs.
However, if the functionality of your design requires holes with non-standard diameters, then a machinist will create these hole features using an end mill tool. Therefore, the same requirements we mentioned for designing cavities also apply here.
#4 Designing Walls
You have to place close attention to the wall thickness when designing walls for CNC manufacturing. This is because thin walls are generally challenging to fabricate accurately due to vibrations from machining.
We recommend that you design walls to have a minimum wall thickness of 0.8 mm for metal parts and 1.6 mm for plastics. The higher wall thickness dimension requirement for plastics is because they are more prone to softening and warping than metals during machining operations.
#5 Designing Text and Lettering
Texts and lettering are quite straightforward to achieve with CNC machining. One thing to note, though: it’s more cost-effective to design parts with engraved texts instead of embossed text. This is because the CNC machine removes lesser material to achieve engraved texts than engrossed texts.
Additionally, we recommend that you use Sans-serif fonts (like Arial, Avenir, Verdana) with a font size greater than 22 points when designing parts with text and lettering.
Preparing Your CNC CAD Design Model for CNC Machining
The CNC CAD design rules help achieve optimized 3D CAD models, allowing any CNC machine shop to create your parts accurately and cost-effectively. However, the CNC machine does not understand these 3D models. Therefore, you need to convert these models into a format compatible with the CNC machine.
An acceptable format for CNC machines is the dxf file format. Most CAD software allows you to save your file in the dxf file format, which can then be imported into a CAM program and converted into CNC programming language (also called the G-code). The G-code then automates the operation of the cutting tool and workpiece to create your product.
CNC Manufacturing Services: Gensun Can Help
This article has presented essential design tips to help you achieve desirable results with CNC machining. However, a lot can still go wrong if you work with the wrong CNC machine shop. You want to work with a shop that has highly qualified CNC machinists, engineers, and quality control experts.
Gensun Precision Machining is a leading provider of CNC manufacturing services across Asia. We’ve been in business for nearly two decades, providing high-quality CNC machining services to customers across a broad range of industries. Our team of highly qualified engineers, machinists, and quality control experts works with you, ensuring you get your product done right the first time.
The product development process encompasses several minor processes, and material selection is the most essential among them.
Every material has different mechanical properties and capabilities. And to make the right material choice, you need to determine the type of loading conditions your part will experience. For instance, if you’re looking to design a part (or assembly) that will make contact with other components or experience impact loading, then you want to choose a material with sufficient material hardness.
But what exactly is material hardness, and how do you measure it? This article answers these questions and more.
What is Material Hardness?
Material hardness is the ability of a material to withstand localized plastic deformation due to concentrated applied loads.
Look at it this way. When we say a material has a high degree of hardness, it simply means the material can retain its shape in the presence of external forces like scratching, indentation and abrasion. So, materials like titanium and diamond would have a higher degree of hardness than plastic.
When comparing diamond and plastics, you probably know which material has greater hardness by intuition. But when you want to choose between closely related metals (or alloys), it’s almost always impossible to make a correct guess unless you perform a hardness test on them.
There are several methods for testing material hardness. But before we discuss these methods, it’s essential that you first understand the types of material hardness.
Types of Material Hardness
Here are the three types of material hardness:
Indentation hardness refers to the resistance of a material to permanent deformation when it is subjected to continuous load. In contrast, scratch hardness describes a material’s ability to resist scratching of its surface due to contact with another metal. Lastly, rebound hardness is related to the material’s elasticity; it describes the ability of a material to absorb the impact energy.
Once you know the type of loading (or environmental) conditions your part will experience, you can then consider any of the following hardness test methods to compare your material options. If you have the equipment necessary, you can complete these tests. Or you can rely on information from your suppliers and online resources like Matweb that list the properties of various materials.
How to Test the Hardness of Materials: 4 Test Methods
The Brinell test measures a material’s indentation hardness. This test method uses an indenter (usually a hardened steel ball) to create an impression on a test piece. In this test method, you will hold the indenter in place before applying a predefined force into the ball (and surface of the material) for a specified period.
Next, assign a Brinell hardness number to the material depending on the size of indentation formed on it. You can measure the indentation using a microscope and calculate the Brinell hardness number using:
Where: HB = Brinell hardness (kg/mm2) P = Force (measured in Newton) D = Indenter diameter (measured in millimeters) d = indentation diameter (measured in millimeters)
However, keep in mind that the predefined force you will apply on the indenter depends on the material you’re looking to test. For instance, quality control experts typically use a standard load of 3000 kg (or 30,000 N) for hard metals like iron and steel. In contrast, you should apply a load of 500kg (or 5000 N) for softer materials like copper and brass.
Method #2 Rockwell Hardness Test
Operator conducting a Rockwell hardness test
Like the Brinell hardness test, the Rockwell hardness test is also used for indentation hardness measurement and typically involves using an indenter (usually steel ball or a spherical diamond-tipped cone).
However, in the Brinell hardness test, you hold the indenter in place by applying a minor load (typically 10 kg or 100 N) before applying the major test load. Then, upon removing the major load, measure the indentation depth while the minor load is still on.
The hardness number can then be read using different Rockwell hardness scales (A, B, C, etc.). The ideal scale depends on the type of indenter used and the test load applied to the material. For instance, let’s say you want to measure the hardness of steel alloys; you would have to use a diamond cone indenter with up to 140 kg of major load. In such a scenario, you will read the hardness number on the “C” scale.
For softer metals like copper alloys, quality control experts use a diamond steel ball (with up to 100 kg of major load) and read the hardness number on the “B” scale.
Method #3 Mohs Hardness Test
The Mohs hardness test is ideal for measuring the scratch resistance of a material. In this test method, you scratch the material’s surface to be tested using a reference material with predefined hardness. The hardness value is expressed using the Mohs scale, which is composed of 10 minerals that have been assigned arbitrary hardness values.
Alan’s Factory Outlet has Mohs hardness chart (screenshot above) on which you can see examples of the scratch resistance of various metals.
Method #4 Shore Scleroscope Hardness Test
The shore scleroscope is a device used to measure a material’s rebound hardness. The device features a graduated glass tube mounted on a stand. To determine the rebound hardness of your material, you’ll drop a diamond-tipped hammer through the glass tube onto the material.
Schematic representation of Shore Scleroscope mounted on a tripod. From Wikimedia Commons.
The hardness value is proportional to the height to which the hammer rebounds after hitting the test piece. For instance, a material with a greater hardness causes greater rebound height than a material with a lesser degree of hardness.
Material Hardness Test and Product Development: Gensun Precision Machining Services
Without a doubt, it is essential to know the hardness of different materials to determine the ideal material for your product design. But even after you choose a suitable material for your product, you still have to find a suitable machine shop and machinist capable of creating your parts accurately and precisely.
Gensun Precision Machining is a leading provider of machining services across Asia. Not only do we have a team of quality control experts capable of testing material hardness, but we also have a team of highly qualified engineers and machinists. Our team of experts works together to create your product accurately and precisely using state-of-the-art machining technologies.
Have you recently come up with a product design, or do you have a product idea that you believe will be the next big thing once it hits the market? If so, you’re likely looking for a manufacturing technology that will create your product accurately without you having to break the bank.
Subtractive manufacturing is among the most widely used manufacturing methods today across many industries because of its high accuracy, precision, and low cost. In fact, Tech Giant Apple had to ditch conventional manufacturing methods and rely on subtractive manufacturing technology to create the unibody enclosure of the MacBook Pro.
But what is subtractive manufacturing, how does it differ from other manufacturing technologies, and how can you use it to solve today’s typical product design challenges? This article answers these questions and more.
What is Subtractive Manufacturing?
Subtractive manufacturing involves creating desired shapes (or products) by successively cutting material from solid blocks of material. This manufacturing method started to gain attention in the manufacturing industry in the 1940s because it allowed machinists to manually fabricate complex parts to optimal accuracy and precision.
And to make things even more interesting, modern-day subtractive manufacturing technologies eliminate the “human factor” in machining―they require little to no input from machinists to achieve even better accuracy and precision than conventional technologies. An example of such modern-day subtractive manufacturing technology is the computer numerical control (CNC) machine.
A CNC machine relies on a computer program (G-code) to direct cutting tools to make the required cuts on a workpiece and achieve the desired shape. A product designer is only required to create a 3D CAD (computer-aided design) model of the part. And the CNC programmer will perform all the tasks necessary to convert this model into G-code, which the CNC machine will use to create the desired parts autonomously.
What is the Difference Between Additive and Subtractive Manufacturing?
Like modern-day subtractive machining technologies, additive manufacturing technologies also rely on 3D CAD models and computer programs to create the desired shape. However, unlike subtractive machining, the additive manufacturing method involves adding materials in layers until you achieve the desired shape. An example of additive manufacturing technology is the 3D printer.
Although 3D printing is gaining momentum in many industries today, it is not likely to replace subtractive manufacturing processes like CNC machining any time soon. For instance, CNC machines’ global market size is currently USD 83.99 billion and projected to surpass USD 128.41 billion by 2028. In contrast, the global market for 3D printing is valued at 12.6 billion.
So what advantages does CNC (or subtractive) machining have over additive manufacturing processes?
What are the Advantages of CNC Machining?
#1 Better Accuracy and Precision
One of the major advantages of CNC machines is their higher accuracy over several types of 3D printing technologies, including SLS (Selective Laser Sintering), FDM (Fused Deposition Modeling), and Direct Metal Laser Sintering (DMLS) technologies. To give you an idea of how CNC machines’ accuracy compares with these 3D printing technologies, Table 1 shows the achievable tolerance limits of these technologies.
The precision (or repeatability) of CNC machines is comparable to 3D printers. However, with CNC machining, you can replicate large quantities of parts in a matter of hours, whereas it might take 3D printers days (or weeks) to produce the same quantity. Simply, CNC machining offers you a shorter lead time compared to 3D printing.
As a product designer, you’d agree that material selection plays a crucial role in the performance and cost of your product. But even after you choose an ideal material for your product, there is still the need to choose a manufacturing technology that is compatible with your material.
CNC machines are compatible with pretty much any metal, plastic, wood, or composite as long as these materials are available in solid blocks. In contrast, 3D printers are only compatible with plastics and a few metals.
#3 CNC Machines Can Fabricate Large and Complex Parts
CNC machines can fabricate extremely large and complex parts, unlike additive manufacturing technologies. For instance, a simple CNC milling machine can create parts with a build volume of up to 2000 x 800 x 1000 mm, whereas SLS 3D printers’ maximum build volume is around 300 x 300 x 300 mm.
Choosing between Additive and Subtractive Manufacturing: Gensun Can Help
Subtractive manufacturing can solve many of the problems you’d encounter in product development. However, this doesn’t imply that subtractive manufacturing is a one-size-fits-all method for manufacturing any design you come up with. Instead, the right manufacturing technology will depend on your product design requirements, and it helps when you work with a machine shop with additive and subtractive manufacturing capabilities.
Thankfully, Gensun Precision Machining is a leading provider of additive and subtractive machining services across Asia. Not only do we have state-of-the-art machining technologies, but we also have highly experienced engineers, machinists, and quality control experts capable of getting your product done right the first time.
Humans’ energy needs were modest before the industrial revolution. For example, we were happy to utilize energy from the sun for heat, horses for transportation, the power of the wind to sail around the globe, and water to drive simple machines that grind grains. Everything changed in the 1780s, with high growth in steam power generation plants, of which most of their components were fabricated using high-speed lathes.
But as the energy needs continued to grow since rapid industrialization began, energy systems and technologies became more sophisticated. As a result, it became more challenging for manufacturers to meet the manufacturing requirements of the energy industry until the advent of CNC machining technology in 1952.
In this article, we will cover CNC machining in the energy industry. We will present three things you must know about CNC machines and their role in today’s energy sector. So let’s get right into it!
#1 CNC Machining is Helping to Fabricate Hydropower Turbines and Generator Components
Hydropower turbines and generators are massive, consisting of hundreds of thousands of components. These components vary in design and size, with some components smaller than your index finger and others larger than the size of a car. Regardless of the variation in size, one key requirement is that these components are machined accurately and precisely to ensure seamless assembly.
CNC machines are among the key machining technologies that product designers use in the energy industry to satisfy these requirements. For example, Canyon Hydro (one of the leading manufacturers of Pelton and Francis hydroelectric turbines) relies on a 7-axis CNC milling machine to fabricate the majority of the components that make up their 36-ft-long and 25-ton hydroelectric systems.
The reason for this high dependence on CNC machines is understandable. First, CNC machines can machine to tolerances as small as 4µm, which pretty much is the tolerance limit you’d find in many hydropower components and parts (like simple shafts, impellers, and bushing). Second, multi-axis CNC machines are particularly suitable for fabricating extremely large and complex geometries.
But CNC machines’ applications aren’t limited to the renewable energy industry.
#2 CNC Machining is Helping to Fabricate Difficult-to-Machine Materials in the Conventional Generators and Turbines
Like the hydropower systems, conventional turbines and generators — which rely on fossil fuels to generate power — feature thousands of components. However, unlike the renewable energy systems, conventional generator components are subjected to extremely high thermal conditions of up to 2300℉, causing engineers to rely on high-strength and thermal resistance materials for these components.
Finding a material with high strength and thermal resistance isn’t a problem for product designers. Instead, the challenge is finding a suitable manufacturing method for these metals. For example, a high-strength material like titanium and its alloys has poor (or average) machinability and is prone to chatter during metal cutting.
Because of CNC machines’ compatibility with a broad range of materials, manufacturers rely on them to fabricate difficult-to-machine metals found in conventional generators and turbines. For instance, skilled machinists usually CNC machine titanium with recommended cutting speeds of 59 m/min for roughing and over 180 m/min for finishing operations.
#3 CNC Machining is Contributing to the Research on Solar and Wind Power Systems
Solar and wind power systems are slowly taking center stage across the globe, replacing conventional energy systems that rely on fossil fuels and contribute to climate change. As a result, research studies are being done to improve the efficiency and performance of these systems. For example, some research scientists are investigating the energy efficiency and performance of novel wind turbine blade designs and solar panels.
And as you may have guessed, CNC machines are among the technologies used for rapid prototyping the blades and solar panels used in most of these research studies. A major reason for this preference is the ease of modifying designs in CNC machining.
With CNC machining, you only need to modify dimensions on your 3D CAD software, and a CNC machinist will have no problem fabricating your new blade (or solar panel designs) quickly. This is not the case with conventional manufacturing methods like injection molding, where you have to start all over by recreating molds.
CNC Machining for the Energy Industry: Gensun Can Help
Now that you understand the role of CNC machining in the energy industry today, you’d agree that CNC machining has been an essential manufacturing method since the industrial revolution. But as much as CNC machines simplify energy parts machining, the success of your project also depends on the machine shop you work with.
You want to work with a machine shop with top-of-the-line CNC machines as well as highly experienced CNC machinists, engineers, and quality control experts.
Gensun Precision Machining has been in business for nearly two decades, providing high-quality CNC machining services to customers in the energy industry. We have state-of-the-art CNC equipment, and our engineers are capable of getting your product done right the first time.