Posts Tagged ‘cnc machine’
CNC: A Company’s Perspective
CNC machine tools are praised all over the world because of three major factors: automation, accuracy and versatility. Human (operator) intervention is reduced to minimal levels because CNC machines can run on its own after it is programmed. Also, when the program is perfected, the CNC machine can run the instructions perfectly on its own.
Remember that any CNC machine can also be programmed to do special one-time tasks such as a dry-run, which will help the operator oversee what will happen when s/he leaves the CNC machine to do its tasks alone. Accuracy also goes hand in hand with repeatability. Again, once the program is perfected, the CNC machine can perform that task PERFECTLY even until 7 or 7000 times.
Lastly, versatility also works in the form of “task memory” that these CNC machines have. Once a program has been performed even for just one production run, it can be easily recollected the next time that the company needs the program. This saves time for setting up and loading of different programs.
The CNC sure simplifies the work of thousands of factories and machine shops worldwide. However, no matter how great CNC sounds like, it is something that doesn’t fit in some industries. Like, perhaps, in the cosmetic industry, or in the show-business. Those examples are way too obvious. On the other hand, in these two major mechanical industries, CNC is almost synonymous to “hero”.
CNC In THE METAL INDUSTRYThink of Metal. Metal. Perhaps the easiest metal that you can imagine is that of…a spoon. Now, imagine ANY spoon done with bare hands. After that, imagine a thousand spoons done with bare hands. It’s so tedious you might even consider suicide if you are assigned to such a job.
The metal industry has been operating on CNC for ages. In fact, if you search CNC in the internet, you will instantly find metal companies topping the list. The major CNC centers that you will find in most metal machining processes are “CNC turning centers”, “CNC machining centers”, “CNC grinding centers” and “CNC drill and tap centers”.
Some of the CNC programs that are connected with the metal industry are milling, drilling, reaming, boring and tapping. Moreover, any metal that has any curved side have experienced some form of knurling, grooving, turning and/or threading.
Fabrication, in manufacturing, refers to processes that are executed on thin plates/sheets. These sheets are cut, punched, and bent to form their finishing shapes. CNC also stars in almost every aspect of metal fabrication.
CNC in THE WOODWORKING INDUSTRYWhile the most beautiful wood-worked products are most likely hand-made, you cannot deny that a wide array of tools and furniture HAVE to be NOT hand-made to save time and for mass production levels. There’s just too much work and not to many hands. In light with this, CNC has worked wonders for this industry.
Important woodworking processes include cutting, framing, carving and engraving. The most useful woodworking CNC product is the CNC router table. It is capable of carving elaborate 2D and 3D designs. Moreover, it is also capable of material change while repeating the same design. Since contemporary furniture is often a splash of different materials (e.g. Wood, aluminum and/or plastic), any CNC router is capable of reproducing the same design EVEN in different kinds of materials by just altering the router bit.
Although many local, middle-sized enterprise owners are skeptical about using employing CNC in their manufacturing operations, there have been many success stories to sway them to using it anyway. In the Metal and Woodworking industries, CNC has proven itself time and again to be efficient.
It saves time and efforts in production and (more importantly) back-jobs. If you’re venturing to one of these industries, remember that the word “labor” isn’t something social anymore – it’s technological. And start calling CNC your best friend.
Incoming search terms:The Different CNC Machines (Types of CNC Machine)
CNC has different applications depending on the machines that operate on it. So if you’re a budding operator, you should know the most common machines that can operate on CNC.
Milling
Milling machines are common CNC machines. These devices are used in the shaping of metal and other solid materials. It is basically a rotating cutter and a table. Milling machines are capable of complex toolpaths as the cutter is not limited to a sideways movement but allows for an “in and out” motion. This movement is precisely controlled by moving the table and the cutter relative to each other. Cutting fluid is then pumped in to lubricate and cool the cut and to remove any swarth that is generated by the cut.
Lathes
Lathes are machines that perform different operations such as sanding, cutting, knurling, deformation, or even drilling. These machines work by spinning various solid objects and then using tools that are symmetric to the axis of rotation. A lathe machine has a single tool in which the workpiece is worked against the tool. The tool is then worked alongside or into the workpiece in order to generate the feed.
Lathes can be used for different operations.
Machining Centers
These are more complex CNC machines that combine milling and turning. As milling was described earlier, turning will be the focus of this section.
Turning is the process by which a central lathe is used in conjunction with the rotation of the material to be turned. The cutting tool is then moved along the two axes of motions to produce accurate dimensions.
Combining turning and milling can produce extremely precise components. And that is what these machines are used for. However, due to the complexity of these machines, operators have to be specialists in order to be able to operate with maximum efficiency.
Electrical discharge machine
An electrical discharge machine (EDM) creates cavities in metals by emitting electric sparks. This process requires an electrode, coolant, a power source, and a tank. The cycle is accomplished by connecting the workpiece to one side of the power supply and then placing it in the tank. An electrode (made in the shape of the cavity required) is then connected to the other side of the power supply.
The tanks is then filled with coolant and the electrode is lowered until a spark jumps between the work and the electrode. As the coolant is a dielectric substance (resists electric currents), it requires a smaller difference in distance in order for a spark to jump through. This means that when the spark appears, the dielectric property has been overcome. The spark then dislodges material thereby creating a cavity in the shape of the electrode.
CNC systemsCNC systems are complex machines that transfer and store data regarding the operation mechanism of the machines. Motion programs include point to point control, straight cut control, and contouring control.
Point to point control means the control of the tools from one point to another in the coordinate plane. This method of control is commonly used in drilling and boring operations.
Straight cut control is the method by which a tool is moved in all axes of the machine. The tool also has the ability to move in a 45 degree angle.
Contouring control is the means to create a toolpath. It moves the tools by interpolating points or coordinates that make up the path for the tool to follow.
Incoming search terms:Motion Control Of CNC Machine
Motion control can be applied in many categories such as robotics, CNC operated machine tools and Kinematics, wherein motion control in kinematics are usually simpler. It can be mainly used nowadays with packaging, textile, assembly industries, printing, and semiconductor production. The hardware of a motion controlled machine usually consists of drive systems, motors, a computer, a PLC or Programmable Logic Controller to run the programs, and an amplifier.
The basic design of a motion control system would include a motion controller to produce a set of points including closing a position, a drive or amplifier to convert the control signal of the motion controller into a high power electrical current, an actuator, one or more feedback sensors, and mechanical components to convert the motion of the actuators to the desired motion.
CNC machines use programmable commands to make inputting motion to the machine easier rather than using cranks or other conventional machine tools. Almost all CNC machine tools can have programmable motion type (whether it would be rapid, linear or circular), the amount of motion, the feedback rate, and the axes to move.
Motion control is the simplest function of any Computer Numerical Control (CNC) machine. It is precise, consistent, and automatic system of control. CNC equipments need two or more modes of direction to which they are called axes. There are two common axis types and they are called linear and rotary. The linear axis type of motion control is driven along a straight path while the rotary axis type is driven along a circular path.
The operator of the motion controlled machine counting the number of revolutions made on the handwheel, added the generations of the dial would accomplish accurate positioning. The drive motor of the machine would be rotated to a resulting amount, which would then drive the ball screw, which would cause the linear motion of the axis. The feedback device at the end of the ball screw would confirm its revolutions.
The same linear motion can be found on a table vise. When you rotate the vise crank, it would also rotate a lead screw, which would then be able to drive the movable jaw in the table vise. In comparison to a motor controlled CNC machine, the linear axis in it is extremely precise compared to that of a table vise. This is because the number of revolutions of the axis drive motor in the CNC machine accurately controls the amount of linear motion along the axis.
A CNC command programmed and executed within a control of a machine would tell the drive motor of the machine as to how many number of precise times it would rotate. This in turn would rotate the ball screw then the ball screw would drive the linear axis. After the process has started, a feedback device located at the end of the ball screw would confirm the programmed number of rotations that the machine would run has taken in effect.
How would axis motion be controlled?
Utilizing a form of coordinate system would make axis controlling a whole lot simpler and more logical to the CNC control. Two coordinate systems that are being used in CNC machines that have been popular are rectangular and polar coordinate system, to which the more popular of the two is the rectangular coordinate system.
Graphing is a common application for the rectangular coordinate system and is needed to cause movement in a CNC machine.
Incoming search terms:The Basic Parts of a CNC Machine
CNC (Computer Numerical Control) machines are in demand in industries where hands are better off pushing buttons than doing actual labor. Businessmen are raving about this wonder-machine because it is accurate, speedy and flexible.
The CNC machine is actually a factory of its own. There are different parts that have specific functions. Let’s get to know the “factory workers”.
THE VICE
The Vice is what holds the material which is to be cut or molded. It is important that the vice must be tight; so the material will be held securely. When the CNC machine starts to operate, the material will dash out of the vice if it is not secured. The vice usually works like a clamp that needs to hold the material not just securely but also in the right position.
THE GUARD
The Guard—just like any other guard—works like a “protection” to the person operating the CNC machine. Once the CNC starts working, scraps of the material can “shoot off” at high speed. This is very risky for the operator if a piece hits him/her. The guard completely covers all the hazardous sides of the CNC machine.
THE CHUCK
The chuck holds the cutting tool. Sophisticated designs require maximum chuck precision so the actual design can be realized.
THE MOTOR
The motor rotates the chuck at very high speed. It is hidden and protected inside the machine. You have to take care of this part very carefully. Nowadays, cooling and lubrication is automated in most CNC machines. Usually, if this part doesn’t function well, it is the most difficult to treat. It is advised to have a CNC technician handy all the time.
THE LATHE BED
Like the sea bed, this is the sturdy base of the CNC machine. It is connected to the headstock and aids the carriage and tailstock to be parallel with the spindle’s axis. It is securely bolted so it remains unshaken by the vibration of the machine when it starts operating.
THE CUTTING TOOL/ CUTTER
This is the where the first-level shaping occurs. The cutter is usually made from high quality steel so as to cut the specific material fed to the CNC machine.
As a businessman, it is important that you get to know your employees, bond with them and earn their respect without scaring them. When you have CNC machines working for you, it is equally important that you understand them well. Do not be fooled by the CNC machine salesmen who court your interest because they are usually just after your purchase.
You have to master what comprises these machines, what makes them dysfunctional and most of all, what makes them stay in your company. Just don’t start talking to them. That would be really, really, dysfunctional.
If you carve your name on a wood using a very sophisticated font, you’re lucky if you’ll finish your first name in 24 hours perfectly. Years ago, wood crafting and metal crafting are very expensive massive- labor industries because every aspect of the manufacturing is done by hand. There was minimal machine intervention but the designs were still as intricate.
Today, with the help of technology, wood carving, metal molding, cutting and even finishing can be done simultaneously with minimal hands involved. In fact, a company is deemed unproductive if it mass produces products every day BY HAND.
Incoming search terms:How to Operate CNC Machine
Computer Numerical Control (CNC) machines setup and how to operate CNC Machine as mentioned in this article. CNC machines are sophisticated instruments that only trained operators should operate them. There are certain rules and guidelines to consider if you are planning to use a CNC machine by yourself.
CNC Machine Checklist Before StartupBefore starting up the Computer Numerical Control Machine, there are safety rules that must be considered first. First important aspect before starting up the CNC machine is to ensure your own safety, therefore wearing protective gear, such as eye glasses and short sleeved shirts is an important dress code during CNC operation. You should also be careful whenever you are handling tools and sharp edged work pieces to avoid any accidents. You must also ensure that the cutting tools are fastened in the machine spindle to avoid any movement during the cutting operation.
CNC Machine Actual Startup, Operation and Machine Setup of the CNCThe Computer Numerical Machine startup procedure varies depending with the type of machine being used but usually there is a main power switch or a circuit breaker to turn it on. Some machines also require hydraulics or air pressure before it starts up.
When the Computer Numerical Machine (CNC) starts up, the machine usually starts at its Machine Home Position. The Machine Home Position allows the control and the machine to have a preset starting position for all its axes. After startup, the CNC machine must be sent to this position before the work begins. This position will later be changed to an appropriate location whenever you are machining a particular part of a product.
The Tool Length Offset Value or TLO is the distance from the tip of the tool from the spindle in the Home Position. The TLO must be set for each tool in the current job. The TLO can be set using a height gage, fixture location, as well as the reference tool. When these values are determined, they are stored in the Controller to be used during the program operation.
After setting the Tool Length Offset Value it is time to setup a part origin of a CNC machine. Setting up the part origin on a CNC machine is the same as setting up a conventional machine. It usually involves positioning the axes to a point where the plan designates as its origin. There are many ways to locate the position on the reference point, it is by using edge finders, wigglers or magnifying glasses.
After setting up the whole system for the Computer Numerical Control, it is time to Load the program to the machine. Program loading is different for each machine. Some machines have tape readers to input the program into the Computer Numerical Control Machine’s memory. Newer machines have internal or external floppy devices to input the program to the machine. After the program is loaded to the machine, the CNC machine is now ready to use.
How to Operate CNC Machine : ConclusionThere are certain instances when you have to change the tools in the Computer Numerical Control manually during machine operations. When a certain machining operation is complete, the program will move the aces to the tool change position and display the next tool needed. It is now the job of the Machine operator to remove and replace it with the next tool.
Extra Care must be taken whenever you are starting operations with the CNC machine, any mistake taken during the part of the operation may lead to serious injuries from the machine operator. More articles on CNC machine at DFS.
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