CNC machine
CNC machine (Numerical Software Control) - a machine whose operation is subject to a predetermined program. Thanks to this, you do not need a person to process the part I drew a part on the computer, set the workpiece in the machine, pressed the start and went to drink tea. Upon returning you get the finished parts from the machine. Fantasy? Not at all, such a machine can be made independently!
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The original article was published on the licrym.org portal . It is published here with abbreviations. As usual - this is the only repost.
The text below will not contain step-by-step instructions on how to cut and where to insert. By understanding the concept and focusing on the details that are available, you can assemble your own, unique version of the machine. If possible, you can buy a ready-made kit for assembly, or order certain components. The result is directly dependent on the accuracy of manufacturing, the number of industrially manufactured parts and perseverance.
We will have a machine with 3 degrees of freedom - translational movements along the X, Y and Z axes. The working field is directly proportional to the length of the guides that we use. Accuracy will largely depend on the build quality.
The machine will be called "Hephaestus".
When creating this machine tool used:
* Screwdriver
* Jigsaw
* Electric wastage
* Threading tools / files / files and other trifles.
Materials:
* Plywood
* aluminum corner
* many cogs and gadgets
* Epoxy glue and epoxy
Details:
* Two stepper motor pushing paper from laser printers,
* Stepper motor to drive the head of the matrix printer
* Guides with bronze plain bearings made from dot matrix printers
* Meter stud M10
Materials are purchased at any hardware store, parts are pulled out of old equipment.
There is a great article where everything is listed on the shelves how to make machines .
Structurally, the design was chosen with a rigid portal, moving along the X-axis table. There were no strict requirements for the machine - it was just interesting to try and there was no desire to spend large sums of money on the experiment. As a result, almost completely the machine was assembled from what was in my bins.
Guides were used from matrix printers, along with native slide bearings. As the driving screws - steel construction studs M10. Nuts on the running screws - the most common - hex.
If there is a possibility - you can buy a ready-made coordinate table, for example, proxxon , the problem with accuracy will disappear immediately.
Z-axis is used furniture guide with balls. On the Internet I saw a machine completely made on such furniture guides.
The quality of the machine is directly dependent on the accuracy of production. Studs, hand-machined on an electrosharpening will give a worse result than studs machined on a lathe. In this case, the studs were cut by hand, as it turned out in the end, with a slight misalignment, which ultimately led to the beats.
The X and Y pins rest on their ends against the ball bearings that are secured with epoxy-liner. The second end of the studs through couplings are connected to the engines. Couplings are made of a piece of steel tube with holes for clamping screws. As a coupling, you can use several layers of heat shrinkable tubing, additionally fastened with nylon ties. In the absence of strong heating, they can give an acceptable result.
Due to the inability to manufacture all the details of the machine precisely (and everything was done manually, practically on the knee), many connections are made on screws, with subsequent adjustment. In the photo machine stand and pre-installed guides with spindle screws:
Table with X-axis drive attached:
After installing the guides, it was necessary to set the bearings with sliding bearings so that they would not be skewed and the table would move along the guides easily. After a fairly long dance with a file, this was achieved and the screws were tightened.
The Y axis drive was made in a similar way:
The Z axis drive does not have a ball bearing at the end of the screw.
In the assembled state, the machine parts should move when the screw is rotated with your fingers without much effort. Otherwise, the engine power may simply not be enough to overcome the forces of friction and deformation due to inaccuracy of the machine.
The proxxon drill is used as a spindle. You can fix any sufficiently powerful engine.
As cutters, you can use dental drills, nozzles for Dremel.
Stepper motors from printers are quite suitable as motors. The larger the engine, the better - more power can be obtained from it. Along the X and Y axes, motors from the paper drive of laser printers are installed; they have 48 steps for one revolution of the shaft. Along the Z axis, a motor is used to drive the head of a matrix printer with 200 steps per shaft rotation. Unfortunately, the complete documentation for the engines could not be found.
Machine mechanics assembled, engines installed. Now we need to do two things - this is the controller that will receive signals from the computer, and include the appropriate motor windings, and the power supply that will feed the whole farm.
The controller is assembled on the basis of L297 and L298 microcircuits as follows.
Photo board assembly:
This is the so-called step / dir controller. The name says that the signal is fed to the input for each axis 2: step (step) and direction (direction). Direction indicates whether the motor is rotating or counterclockwise. Each step pulse will rotate the motor shaft by exactly one step.
The power supply is a simple transformer, with a smoothing capacitor. You can use a computer power supply.
Controller with power supply:
The controller connects to the computer via the LPT port.
Without a program, the machine is just a pile of iron. CNC machines are usually controlled by a G code that is standardized. First of all, we need a program that would accept at the input some sequence of G commands and give the necessary impulses to the LPT port to which we have a driver connected.
Examples of such programs:
TurboCNC (works under DOS)
Mach3
KCAM
Linuxcnc
I used Mach3, the screenshot of which is below:
Included with Mach3 is the LazyCAM program into which a dxf file with a picture was loaded, which was turned into a set of control G-codes. These codes were sent to mach3 and processing started.
Tests with a felt-tip pen:
Here is the process of engraving the department logo with the machine:
Engraved logo:
As you can see the machine works. On the engraving took about 15 minutes. Due to the inaccuracy of processing tails of the studs and the inaccuracy of manufacturing parts, there are beats, for example, the waviness of the line at the top of the Christmas tree is visible, the waviness step of 1.5 mm corresponds to the thread pitch.
The actual accuracy of the machine goes about 0.5 mm. The maximum movement speed is 200 mm / min. Working field 230 * 230 mm.
Engraving.
Automatic drilling of printed circuit boards
Cutting plastic parts
Coordinate burning (example: www.vri-cnc.ru/modules.php?name=News&file=article&sid=30 )
Wood carving
and many other uses.
')
The original article was published on the licrym.org portal . It is published here with abbreviations. As usual - this is the only repost.
The text below will not contain step-by-step instructions on how to cut and where to insert. By understanding the concept and focusing on the details that are available, you can assemble your own, unique version of the machine. If possible, you can buy a ready-made kit for assembly, or order certain components. The result is directly dependent on the accuracy of manufacturing, the number of industrially manufactured parts and perseverance.
We will have a machine with 3 degrees of freedom - translational movements along the X, Y and Z axes. The working field is directly proportional to the length of the guides that we use. Accuracy will largely depend on the build quality.
The machine will be called "Hephaestus".
Tools and materials
When creating this machine tool used:
* Screwdriver
* Jigsaw
* Electric wastage
* Threading tools / files / files and other trifles.
Materials:
* Plywood
* aluminum corner
* many cogs and gadgets
* Epoxy glue and epoxy
Details:
* Two stepper motor pushing paper from laser printers,
* Stepper motor to drive the head of the matrix printer
* Guides with bronze plain bearings made from dot matrix printers
* Meter stud M10
Materials are purchased at any hardware store, parts are pulled out of old equipment.
Mechanics
There is a great article where everything is listed on the shelves how to make machines .
Structurally, the design was chosen with a rigid portal, moving along the X-axis table. There were no strict requirements for the machine - it was just interesting to try and there was no desire to spend large sums of money on the experiment. As a result, almost completely the machine was assembled from what was in my bins.
Guides were used from matrix printers, along with native slide bearings. As the driving screws - steel construction studs M10. Nuts on the running screws - the most common - hex.
If there is a possibility - you can buy a ready-made coordinate table, for example, proxxon , the problem with accuracy will disappear immediately.
Z-axis is used furniture guide with balls. On the Internet I saw a machine completely made on such furniture guides.
The quality of the machine is directly dependent on the accuracy of production. Studs, hand-machined on an electrosharpening will give a worse result than studs machined on a lathe. In this case, the studs were cut by hand, as it turned out in the end, with a slight misalignment, which ultimately led to the beats.
The X and Y pins rest on their ends against the ball bearings that are secured with epoxy-liner. The second end of the studs through couplings are connected to the engines. Couplings are made of a piece of steel tube with holes for clamping screws. As a coupling, you can use several layers of heat shrinkable tubing, additionally fastened with nylon ties. In the absence of strong heating, they can give an acceptable result.
Due to the inability to manufacture all the details of the machine precisely (and everything was done manually, practically on the knee), many connections are made on screws, with subsequent adjustment. In the photo machine stand and pre-installed guides with spindle screws:
Table with X-axis drive attached:
After installing the guides, it was necessary to set the bearings with sliding bearings so that they would not be skewed and the table would move along the guides easily. After a fairly long dance with a file, this was achieved and the screws were tightened.
The Y axis drive was made in a similar way:
The Z axis drive does not have a ball bearing at the end of the screw.
In the assembled state, the machine parts should move when the screw is rotated with your fingers without much effort. Otherwise, the engine power may simply not be enough to overcome the forces of friction and deformation due to inaccuracy of the machine.
The proxxon drill is used as a spindle. You can fix any sufficiently powerful engine.
As cutters, you can use dental drills, nozzles for Dremel.
Engines
Stepper motors from printers are quite suitable as motors. The larger the engine, the better - more power can be obtained from it. Along the X and Y axes, motors from the paper drive of laser printers are installed; they have 48 steps for one revolution of the shaft. Along the Z axis, a motor is used to drive the head of a matrix printer with 200 steps per shaft rotation. Unfortunately, the complete documentation for the engines could not be found.
Electronics
Machine mechanics assembled, engines installed. Now we need to do two things - this is the controller that will receive signals from the computer, and include the appropriate motor windings, and the power supply that will feed the whole farm.
The controller is assembled on the basis of L297 and L298 microcircuits as follows.
Photo board assembly:
This is the so-called step / dir controller. The name says that the signal is fed to the input for each axis 2: step (step) and direction (direction). Direction indicates whether the motor is rotating or counterclockwise. Each step pulse will rotate the motor shaft by exactly one step.
The power supply is a simple transformer, with a smoothing capacitor. You can use a computer power supply.
Controller with power supply:
The controller connects to the computer via the LPT port.
Software
Without a program, the machine is just a pile of iron. CNC machines are usually controlled by a G code that is standardized. First of all, we need a program that would accept at the input some sequence of G commands and give the necessary impulses to the LPT port to which we have a driver connected.
Examples of such programs:
TurboCNC (works under DOS)
Mach3
KCAM
Linuxcnc
I used Mach3, the screenshot of which is below:
Included with Mach3 is the LazyCAM program into which a dxf file with a picture was loaded, which was turned into a set of control G-codes. These codes were sent to mach3 and processing started.
Tests
Tests with a felt-tip pen:
Here is the process of engraving the department logo with the machine:
Engraved logo:
As you can see the machine works. On the engraving took about 15 minutes. Due to the inaccuracy of processing tails of the studs and the inaccuracy of manufacturing parts, there are beats, for example, the waviness of the line at the top of the Christmas tree is visible, the waviness step of 1.5 mm corresponds to the thread pitch.
The actual accuracy of the machine goes about 0.5 mm. The maximum movement speed is 200 mm / min. Working field 230 * 230 mm.
Application
Engraving.
Automatic drilling of printed circuit boards
Cutting plastic parts
Coordinate burning (example: www.vri-cnc.ru/modules.php?name=News&file=article&sid=30 )
Wood carving
and many other uses.
Source: https://habr.com/ru/post/68215/
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