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cnc basics (building a cnc machine part 1)

by:Transon     2020-12-07
So you want to learn more about how to make CNC machines?
Whether it\'s a 3D printer or some type of mil, this will take you to the basics and give you a good idea of how they work, operation and the parts you need or can choose from.
First of all, I have built my own CNC router which works very well and is currently using printers, routers and laser cutting machines.
What is this CNC?
CNC represents computer numbers (ly)
In short, it can work with your computer 1 s and 0 s to signal your motor to start, stop, run and reverse when you want it.
I suggest you find it online if you want to know more, there are a lot of good explanations there.
The next steps will take you through the different main parts of the machine and the information you need to know to make the most of it, and understanding them will help you find a lasting machine.
The basics of a CNC router, lathe or 3D printer are almost the same, the biggest difference is how they operate and control, the router and the lathe remove the material from the material they are using to achieve their goal, the 3D printer adds it, but no matter what system you want to build, the main components are the same.
The guide will consist of different parts, focusing on different aspects of the build.
Guide you all the way to create miracles of your own!
Please also comment on my work (
In any constructive way)
And ask questions you like!
This way I can improve the guide while working.
Thank you. what is the CNC machine made?
For the main electrical part, it will be run by a simple termsThe computer that will run your program to send program signals to the splitter board, which the board will turn into a new signal that will run
The PSU can power your motor and/or the breakout board limit switch and all the other good things you can install on the machine.
Limit switches are not required, but they are good because your machine will know when and where to stop before it runs itself, which can damage the machine.
The main mechanical components are: the frame of the machine is very obvious, it holds all the other parts in the appropriate position, and gives the machine the required stiffness to work on the object, the transmission is to transfer the motion of the motor to your shaft, which will be introduced later.
The bearings hold the spindle in its proper position, and if you use the correct bearing type, they even help to reduce the strain on the spindle.
The coupler is the actual coupling between the motor and the spindle.
These guidelines are used to guide your linear motion and remain stable while the machine is working.
So now you should know what the basic CNC machines are made of and what happens when we put them together?
Depending on the machine, there will usually be 3-
4 axis to worry about, an X, Y,-Z-, and C-
AxisIt works like a coordinate system in which you have X moving forward and backward, Y on the left, motion on the right, Z representing ups and downs, if you have a fourth axis, it will control the rotation of your work object as shown in the first picture.
This is almost the basics of the CNC machine itself and they may vary depending on the machine, but all of this will be introduced later.
The basic operation of the computer.
So how does the computer know where to go and what signal does it send out?
It\'s a bit complicated, but in short, you need a program that can explain the drawings and generate the code you need.
There are different programs that can do this, but what you need to look for is to be able to generate G-code or an M-
Code, which can be done in a drawing program or in a program called a computer-aided manufacturing program (CAM)
Then transfer the code to your control software from where you can run the code.
The type of machine usually has two main types of CNC machines, one is movable on the working surface and the other is movable on the gantry, which is the basis of the CNC machine.
All in all, here is to remember the main content of the computer running the breakout plate, the plate controls the motor coupled with the spindle, where we have our guide rail, the bearing and what we want to move.
There are several ways to start the CNC project from where, but before starting to consider the following: the dimensions of the marking machine can be done in several ways, you can decide the maximum frame width, length, or height, measure the size from the size of the effective working area you want or the size of the spindle.
Decide and stick to these measurements as early as possible.
Remember, your motor may stick out your frame according to the design.
In addition, the frame needs to be able to absorb vibration when the motor is running and changing direction.
Planning your project will save you a lot of time and money, either buy a good one or spend some time in front of your drawing/computer.
While building, have a good plan in your back pocket to get you to order the right parts for the first time and tell you where and when to do it.
The material using this choice will seriously affect the way your frame is built, the \"lighter\" material you choose, the lighter structure, the soft wood, the foam and other materials aluminum on the soft end, the heavy end material is iron, steel, stainless steel, for those of you who need a highly robust machine to get smooth results.
Also, avoid using wood as a frame if possible, I know it\'s cheap and easy, but what you want will continue to be precise and you need a metal frame, because the wood is alive, it can bend, shrink, and expand.
This is the tool I \'ve seen a lot of cheat tutorials, and they detail their work and all of a sudden, \"Oh, I have a friend who has a huge machine, can cut all my parts \"better tool (high accuracy)
You will get better results!
This is not to say that it cannot be done by hand, but the results may vary and you end up with some parts that you have to redo to make things clearer and more uniform.
So consider how much it will cost you if you have tools or you have to buy finished parts.
However, the right tools and the right materials will help you a lot.
It will depend on the material you want to use, the stepping motors and servo motors of various shapes and sizes, and the amount of torque they deliver should be enough to pull or push the load you add to them.
This is the place you have to pay attention to, using the right system, the right place, the screw bars are not the main shaft, they are used to bolt and hold things together!
You will see a lot of people using them because they are cheap and easy to buy.
But they don\'t last long because they never intended to be used for this kind of use or use belts (
Avoid belt drive Zaxes though)
, Ladder thread or ball screw, each has its own advantages and disadvantages, the back will cover.
This is a matter of taste, really, fixed gantry is easier to build and is the most commonly used type of CNC machine, which usually allows for stronger construction and stronger gantry support, and better bottom-up support.
The movable gantry takes up less space at runtime, but it is a bit difficult to build and run stably, and it is a bit less supported.
If you know where there is an old router or workbench, or you already have one, you can make a CNC machine from scratch, regardless of size, or modify an existing machine, it is very simple to get it into the CNC machine, think about it, everything is already there, it only needs some Motors to run the shaft, you can connect the rest.
Where do you start now you have something to consider, it is important that you make up your mind here, stick to a plan, redesign in the middle of the project can be very expensive, and the time cost is very high.
However, it is important that you find your overall size, either by defining your work area, the maximum frame size that you can accommodate, or in your house, the type of material you want it to use, in terms of the dimension of other parts, which will help you a lot.
So far, you should know something about what you need and why you need it, and it\'s time to look deeper at what you can get.
Next, we will look at the mechanical parts.
This is where prices and precision are really combined, and a completely stable and supported, long lasting machine will never be cheap!
That\'s why industrial machines are so expensive.
So this is where you need to think about it?
Although the 3D printer only needs to be installed stably and safely, the router needs to be more sturdy because it will press the high-speed tool on it with some kind of material.
From experience, you need materials that are stronger/thicker than the material you will be using.
Try using your material the way you expect it.
The framework, as mentioned earlier, is something that supports the whole thing, and that\'s your design --
Skills start to work, there is no right and wrong way to design this part, as long as you remember the power that affects the framework, some people will say that in order to get the best results, you have to turn the gantry into a special design, yes, it\'s true if you want it to be as thin as possible, but if you don\'t have the ability to calculate the force load that affects your machine, there is also a trick, which may not always be beautiful in terms of size labeling or reinforcement, but the first batch of 3D printers, CNC routers or mils is not something that looks good either.
When you work or get things done, you will most likely have to optimize your design.
Avoid setbacks here and keep them as simple as possible.
I know there are a lot of beautiful pictures showing different cool frames, but they are likely to have more advanced parts made by another machine, which will be expensive unless you have that goodfriend-to-pull-out-of-your-hat-trick.
However, I always recommend not to use wood or plastic to build the base frame, yes it is cheap and easy to use, but it will not give you a stable machine in the long run!
As I mentioned earlier, Wood is a creature and any carpentry will tell you this, which is bad when it comes to precision!
One day, you may get very good results, and then you will have a rough journey.
This is not only the product you are developing, it will also affect your mechanical parts and increase their strain.
Also, if the bed is movable and the gantry is fixed, it is also important to decide your bed type here (
Since the first build is simpler, I would suggest this)
Or it should be a fixed bed and a movable gantry as this will affect your overall design.
Well, you have a basic framework to work with some sketches, and it\'s time for that, so it\'s time to decide what guidelines to use.
The tour guide is very important and more important is the restriction of your tour guide.
So let\'s take a look at the different types of guides you can use.
Because there are many different, there are mainly 4 main types of guide rails, rods, guide rails, support rods and DIY-way-to-
Goprettes rods are commonly used as they are both cheap and easy to use.
But they have a huge drawback, they are easy to bend, and a normal suggestion is that for machines with a length of less than 500mm, you should only use rods, otherwise, when they are under pressure, they will become too soft and bend too much.
I tested this myself on a prototype and even if I used a twice the size stick, I still had the same problem.
A bigger problem with the rods is that there is no way to reinforce them except to increase the size.
Also, I looked at some papers doing high-end math on the stick, showing that even without any weight to pull them down, their own weight was enough for the purpose, although it only has a millimeter score.
Also, you should avoid normal iron, pipes, plastic pipes, etc.
Using stainless steel or better real precision rods that are stainless steel and hardened, the ball bearings do not wear out over time.
If the bars are correct for you, here\'s how to install them: you need about 6 bars, X-based on your design-, Y-, and Z-
Shaft, about 12 bearings.
The rails are in the expensive part of the rails, but they are well worth it depending on the type of rails, and you can support them as you like, as they are mounted on a flat surface.
The lower side of the rails is that they are very sensitive to dirt, so they do require more protection than the rod.
I did some research on the rails and it seems that there is not much difference between the smaller ones and the larger ones in the manufacturing price.
The smaller size at around 15mm will take about 10-
Before they start to fail, 20 tons of pressure, more pressure will be greater.
The price difference is the material for extra use.
So, if you\'re going to use this solution, it\'s OK to be small.
The track is relatively easy to install, and if you buy the right place, you will even get good guidance on how to install the first track, and then use the first how to install the other.
According to your design, you need about 4-6 rails.
It is better to place two rails on each axis, but there is only one rail on the Y and z axes and other designs. Support Rod (
Also called rails\"Wait!
You just said you can\'t do that!
\"Yes, but some engineers think it should be possible, but they are more of a combination of rods and rails than anything else.
This is basically achieved by cutting out wedges from ordinary bearings, and also by providing space for the support bar.
It\'s cheaper than the railway, but it\'s still a little more expensive than the pole.
They are installed in the same way as the guide rail.
Again, you need 6 of them according to the design.
2 each axis. The DIY-
Guide common DIY guide is 4 ball bearings on 90 degree angle profile.
It\'s easy to make, cheap, and sturdy, but it can be a bit difficult to install, there are a lot of ways to do it, but to some extent, weld, stick them to drill holes
If you know what you\'re doing and have the time, patience and tools to make it just right, then good results can be archived.
So now that we have the guide rail, let\'s take a look at the transfer method of the mechanical heart of the machine.
In this category, we have three main types of motion to our machine, whether using a spindle, a belt or a gear.
Spindle I want to cover three \"spindles\" here, one of which is not a spindle at all, but many DIY people use them for some reason, I don\'t know if they use it because they\'re cheap or because they don\'t know their replacement, anyway, it hurts me to see people work so hard for a cool result, just to find a shortcut and finally force them to recreate some parts.
The first wrong way is to use simple screw bars and bolts, they are easy to get and cheap, it will be the result of your hard work, because you will change these bulbs as often as you change them for a cheap used bulb with water in it.
They are not made for this use at all, the threads will tear quickly and increase the rebound during use.
Treaded rods and bolts are used to connect your stuff together and make sure they stay where you want them to be and they are good at it, so use them as expected.
If you have to use a screw bar, use at least a copper bolt.
A real spindle is like a screw bar, but the thread is very thoughtful and durable, mainly two, cheap ladder spinner, and one of the most widely used spindles in the world, but its downside is its rebound, and some programs can compensate it, but the better way to deal with it is
Eliminate the rebound system of all this.
The most popular ladder spindle is usually made of copper because copper is considered to be self-containedlubricating.
The other is the ball screw, which is also an expensive range in the industrial world, but on larger machines they are worth it, since the high-end ball screw will not rebound even for high-performance machines.
However, the downside is that they are very sensitive to dirt.
No matter what type of spindle you choose, remember to support both ends of it with bearings designed to work, I know there are some DIY bearings outside, but make sure the bearings are \"flexible\" enough \", give a point from the strain it may get, which will eventually avoid long-term damage to the spindle.
Belts can also be used to push something forward using belts. This is also a cheap and simple way to move the axis, but it has some limitations, first of all rubber, it is worn, good belt is not cheap, cheap belt will slowly relax, the belt breaks if the tension is too high.
Also, I would never suggest in de Z-
Shaft, I have seen some systems use it, but the weight of the shaft will put a lot of pressure on it, in addition, the shaft needs to be forced into the material you are using, and stay there steadily for a while, there may be some problems with the belt drive.
So if you can use the spindle here!
Gears are not round and they can also be long and flat and although I have no experience with this type of transfer I see someone using it and my guess is, it may only work well in some cases and may not be suitable for Z-axis.
The electrical part is the main nerve and brain of the machine;
It can not only run your system, but also provide you with many features and security.
Remember, I can\'t say these and never use them when the electrical components are on or running!
Always turn them off and remove their power!
The computer is the brain of the machine, or at least the brain that directs everything when you look!
If you want to make all the drawings and code on the same computer, then I suggest you buy a decent computer that can run the load of the program, if you only want it to run your machine with commands, then an old computer is enough and a lot of breakout boards still use parallel cables (
Old printer cable)
So, either make sure your computer is compatible with them, because the USB solution can be expensive if your break is not supported by the manufacturer, sadly this is a normal converter (
From USB to parallel port)
This will not be done because the agreement is different.
Personally I have an old computer just to run my router and it\'s cheap and I don\'t need to care too much about it.
The Breakout board the breakout board is a machine neural system that sends and explains all signals to form an emergency stop for the motor (
Although you should always email
Stop cutting all power from the system)
, When there are many breakout boards outside, in order to limit the switch, or you can make one yourself, I suggest you do some research on the board before you buy it, some models are closed, it\'s almost a secret source and it\'s hard to figure out if something goes wrong.
Therefore, please ask for support to the board.
The Breakout board mainly has two types: the \"controller\" board and the \"fully integrated\" board.
The controller board only controls the signal and relies on another driver to run the actual motor.
This takes up more space, and I\'m not sure if this method has any big advantages over another one.
All the integrated boards need only one power supply, and then it can handle everything from running the motor to monitoring the signal.
Compared to the fact that running the motor does not require a drive, it takes up less space and costs less.
Again, I don\'t see any big advantage over the other one.
So just choose what works best for you and what you can get the best support.
Power supply unit (PSU)
It\'s very important that you determine if you need one or more systems to run your entire system.
Definitely make sure to find the right PSU here, because the low voltage PSU can\'t start your system, and the over voltage PSU will almost instantly burn your chipset, motor!
The power supply must fit into your system, and most distributors can tell you what to get based on what you have.
Remember again, after any electrical parts turn on, power off, and remove the power completely, never use any electrical parts before using them, which means that when the device is connected, unplug it!
Also keep in mind that PSUs does get hot while working, so when you place them, it\'s better to put them where there\'s a little space around and cool them a little.
There are two kinds of motors for CNC machine tools, one is stepping motor and the other is servo motor. their structure and control methods are completely different, I can have a long discussion of their principles, and it can be said that the servo system is a mechanical construction, controlled with gears and pulse length.
The stepping motor is more like the little brother of the motor, which uses a magnetic field to turn and hold the position, and is controlled by changing the magnetic field inside the motor.
I suggest you search dos a servo-if you would like to know more-
/Working with stepping motor.
Remember that the bigger motor you get is the heavier load you can push/pull, always trying to get the minimum weight/resistance on your shaft, so, you can just keep the electricity where you need it.
The limit switches have various shapes and sizes, but they all do the same thing and they turn on and off when there is something close or touching them.
They need their own power sometimes (
This is common in proximity sensors)
Send a signal.
A good suggestion is to set up your switch to send the signal when the signal is not active and not send the signal when the signal is active.
This is called a negative signal and can be done in most programs running the machine.
Here\'s the reason.
If you set the switch to be active on touch, they will only send a signal if the machine is at the end of the work area.
The problem is that if the switch has some sort of fault, or if one of your wires breaks, cuts or falls off, the switch does not signal that the machine is at the end of the line, it will run straight into your frame and there is a good chance of damaging something!
This can be avoided by doing the opposite, setting the switch to not send a signal when it is activated, in which case if there is a faulty connection somewhere, you will receive a warning once you start your system.
This is a common practice for almost all security systems.
The most common thing about bundling is probably to buy a bundle where you can buy your motor, PSU, drivers (if needed) and breakout boards, so that, if you\'re not entirely sure how things fit together, you\'re sure the bundle will fit your needs.
The extras have a variety of extras to add to your machine, depending on what you want to have or see, one of the most common things to add is the monitor with the computer DRO (
Digital read output
This screen tells you where your machine is in X, Y, Z, C coordinates.
There is also a display that shows the voltage or amperage the system is using, which can be used to view the pressure of the system, the greater the pressure, the more juice you need to run.
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