Sometimes you need to sign a gift beautifully, but it’s not clear how to do it. The paint spreads and wears off quickly, a marker is not an option. Engraving is best suited for this. You don’t even have to spend money on it, since anyone who knows how to solder can make a laser engraver from a printer with their own hands.
Design and principle of operation
The main element of the engraver is a semiconductor laser. It emits a focused and very bright beam of light that burns through the material being processed. By adjusting the radiation power, you can change the depth and speed of burning.
The laser diode is based on a semiconductor crystal, on top and bottom of which there are P and N regions. Electrodes are connected to them, through which current is supplied. Between these regions there is a P - N junction.
Compared to a regular laser diode, it looks like a giant: its crystal can be examined in detail with the naked eye.
The values can be deciphered as follows:
- P (positive) area.
- P - N transition.
- N (negative) area.
The ends of the crystal are polished to perfection, so it works as an optical resonator. Electrons, flowing from a positively charged region to a negative one, excite photons in the P-N junction. Reflecting from the walls of the crystal, each photon generates two similar ones, which, in turn, also divide, and so on ad infinitum. The chain reaction occurring in a semiconductor laser crystal is called the pumping process. The more energy supplied to the crystal, the more it is pumped into the laser beam. In theory, you can saturate it indefinitely, but in practice everything is different.
During operation, the diode heats up and must be cooled. If you constantly increase the power supplied to the crystal, sooner or later there will come a time when the cooling system can no longer cope with heat removal and the diode will burn out.
The power of laser diodes usually does not exceed 50 Watts. If this value is exceeded, it becomes difficult to do effective system cooling, so high-power diodes are extremely expensive to produce.
There are semiconductor lasers of 10 kilowatts or more, but they are all composite. Their optical resonator is pumped by low-power diodes, the number of which can reach several hundred.
Compound lasers are not used in engravers because their power is too high.
Creating a laser engraver
For simple work, like burning patterns on wood, you don’t need complex and expensive devices. A homemade laser engraver powered by a battery will be sufficient.
Before making an engraver, you need to prepare the following parts for its assembly:
Remove the write head from the DVD drive.
Carefully remove the focusing lens and disassemble the head housing until you see 2 lasers hidden in heat-distributing casings.
One of them is infrared, for reading information from the disk. The second one, red, is the writing one. In order to distinguish them, apply a voltage of 3 volts to their terminals.
Pinout:
Be sure to wear dark glasses before testing. Never test the laser by looking at the diode window. You only need to look at the reflection of the beam.
You need to select the laser that lights up. You can throw away the rest if you don’t know where to use it. To protect against static, solder all leads of the diode together and set it aside. Saw off a 15 cm section from the profile. Drill a hole in it for the clock button. Make cutouts in the box for the profile, charging socket and switch.
The schematic diagram of a DIY DVD laser engraver looks like this:
Tin the contact pads on the charge control board and holder:
Using wires to pins B+ and B- of the charge controller, solder the battery compartment. Contacts + and - go to the socket, the remaining 2 go to the laser diode. At first wall-mounted Solder the laser power circuit and insulate it well with tape.
Make sure that the terminals of the radio components do not short circuit with each other. Solder a laser diode and a button to the power supply circuit. Place the assembled device in the profile and glue the laser with heat-conducting glue. Secure the remaining parts with double-sided tape. Reinstall the tact button.
Insert the profile into the box, bring out the wires and secure it with hot glue. Solder the switch and install it. Do the same procedure with the charging socket. Using a hot glue gun, glue the battery compartment and charge controller into place. Insert the battery into the holder and close the box with the lid.
Before using it, you need to set up the laser. To do this, place a sheet of paper 10 centimeters from it, which will be a target for the laser beam. Place the focusing lens in front of the diode. By moving it further and closer, achieve a burn through the target. Glue the lens to the profile in the place where the greatest effect was achieved.
The assembled engraver is perfect for small jobs and entertainment purposes such as lighting matches and burning balloons.
Remember that the engraver is not a toy and should not be given to children. The laser beam causes irreversible consequences if it comes into contact with the eyes, so keep the device out of the reach of children.
CNC device manufacturing
For large volumes of work, a conventional engraver will not cope with the load. If you are going to use it frequently and a lot, you will need a CNC device.
Assembling the interior
You can even make a laser engraver at home. To do this, you need to remove the stepper motors and guides. They will drive the laser.
Full list necessary details as follows:
Connection diagram for all components:
View from above:
Explanation of symbols:
- Semiconductor laser with heatsink.
- Carriage.
- X-axis guides.
- Pressure rollers.
- Stepper motor.
- Drive gear.
- Toothed belt.
- Guide fastenings.
- Gears.
- Stepper motors.
- Sheet metal base.
- Y axis guides.
- X-axis carriages.
- Toothed belts.
- Mounting supports.
- Limit switches.
Measure the length of the guides and divide them into two groups. The first will contain 4 short ones, the second - 2 long ones. Guides from the same group must be the same length.
Add 10 centimeters to the length of each group of guides and cut the base to the resulting dimensions. Bend U-shaped supports for fastenings from scraps and weld them to the base. Mark and drill holes for the bolts.
Drill a hole in the radiator and glue the laser in there using heat-conducting glue. Solder the wires and transistor to it. Bolt the radiator to the carriage.
Install the guide rail mounts onto the two supports and secure them with bolts. Insert the Y-axis guides into the mounts, put the X-axis carriages on their free ends. Insert the remaining guides with the laser head installed on them. Place the fasteners on the Y-axis guides and screw them to the supports.
Drill holes in the places where the electric motors and gear axles are mounted. Reinstall the stepper motors and place the drive gears on their shafts. Insert into the holes pre-cut from metal rod axles and secure them epoxy glue. After it hardens, place the gears and pressure rollers with bearings inserted into them onto the axles.
Install the timing belts as shown in the diagram. Pull them tight before fastening. Check the mobility of the X-axis and laser head. They should move with little effort, rotating all the rollers and gears through the belts.
Connect wires to the laser, motors and end switches and tie them together with zip ties. Place the resulting bundles in movable cable channels and secure them to the carriages.
Lead the ends of the wires out.
Case manufacturing
Drill holes in the base for the corners. Step back 2 centimeters from its edges and draw a rectangle.
Its width and length repeat the dimensions of the future body. The height of the case must be such that all internal mechanisms fit into it.
Explanation of symbols:
- Loops.
- Tact button (start/stop).
- Arduino power switch.
- Laser switch.
- 2.1 x 5.5 mm socket for supplying 5 V power.
- Protective box for DC-DC inverter.
- Wires.
- Arduino protective box.
- Housing fastenings.
- Corners.
- Base.
- Legs made of non-slip material.
- Lid.
Cut out all the body parts from plywood and fasten them with corners. Using the hinges, install the cover on the body and screw it to the base. Cut a hole in the front wall and insert the wires through it.
Assemble from plywood protective covers and cut holes in them for buttons, switches and sockets. Place the Arduino in the housing so that the USB connector matches the hole provided for it. Set up DC-DC converter for a voltage of 3 V at a current of 2 A. Secure it in the casing.
Reinstall the button, power socket, switches and solder electrical diagram engraver together. After soldering all the wires, install the casings on the case and screw them with self-tapping screws. For the engraver to work, you need to upload the firmware to the Arduino.
After flashing the firmware, turn on the engraver and press the “Start” button. Leave the laser turned off. Pressing the button will start the calibration process, during which the microcontroller will measure and remember the length of all axes and determine the position of the laser head. After its completion, the engraver will be completely ready for work.
Before you start working with the engraver, you need to convert the images into a format understandable for Arduino. This can be done using the Inkscape Laserengraver program. Move the selected image into it and click on Convert. Send the resulting file via cable to the Arduino and start the printing process, turning on the laser first.
Such an engraver can only process objects consisting of organic substances: wood, plastic, fabrics, paint coatings and others. Metals, glass and ceramics cannot be engraved on it.
Never turn on the engraver with the lid open. The laser beam, entering the eyes, concentrates on the retina, damaging it. Reflexively closing your eyelids will not save you - the laser will have time to burn out an area of the retina even before they close. You may not feel anything, but over time the retina will begin to peel off, which can lead to complete or partial loss of vision.
If you catch a laser “bunny”, contact an ophthalmologist as soon as possible - this will help avoid serious problems in the future.
So. We stopped drinking, we’ve already assembled the milling cutter, we bought an Arduina, our arms are gradually straightening - soon we’ll be completely like Homo Sapiens. And he, as you know, is used to creating problems for himself, like a Chinese Komsomol member, and then solving them. Such is the Russian character.
From "nothing" we will need:
Arduino Uno
Shield with a pair of StepSticks
Laser.....as an option it’s easier to purchase, but if you have an inquisitive mind, you can pick up a DVD
Two old CD/DVD ROMs, better than the old ones
Power supply 12 volts....amps so little 2-3-5-10 it doesn’t matter at all
A little drill, a few M4 and M3 screws
Two pieces square pipe 20x20mm and length 180mm
Chip ULN2003 letters can be different - for us the numbers 2003 are important. This chip is often used in old Mastek scanners to control the stepper motor.
In general, the real owner of such rubbish usually has plenty....
If you don’t find Arduino in the house, you can search, for example, on Avito or AliExpress
It’s better to order the shield in advance too... for example 3D Printer Engraving Machine A4988 Drive Extension Board CNC Shield V3 For Arduino + StepStick 2 pcs walkera new v120d02s 6ch 3d rc remote control helicopter bnf green (Red)
If for some reason there is no laser in the trash, you can look for it here: 405nm 50mW Focusable Violet Dot Laser Module Laser Generator Diode Focusable Laser Module Red Dot Laser Generator Diode 200-250mW 650nm , 450-500mW Violet Laser Module With Holder For Mini Engraving Machine And suddenly it was time for horror stories.Friends, when dealing with a laser, be careful not to get direct or even reflected laser beams into your eyes. You can lose your sight forever. It is best to carry out all work wearing special glasses, which are always sold in departments selling laser lasers. diodes.
Well, if you can’t wait until the Chinese send the long-awaited package, you can experiment with a laser diode from DVD-RW. I'll stop at the last one. When disassembling a recordable DVD, be careful - it usually uses two diodes - one with a visible (usually red) radiation spectrum, the second with an invisible infrared one. I highly recommend not using the second one in terms of security.
To test the LED, we connect a regular 1.5 volt battery to it. If the radiation is red, everything is ok. .1421879657252.prev.jpg)
Let's start messing around....excuse me...disassembling the CD-roms. Straighten the paperclip and push it into the hole in the front of the device. The disk compartment will open, remove the compartment cover and remove the screws. Then everything is the same as everywhere else.
I immediately glued the compartment lid to the front panel
We throw out the tray, the boards, and in general free up the internal space of the former DVD case as much as possible. This is where we will subsequently install the power supply
I plugged in the power supply from some HP printer, converting it from 38 volts to 12. Its power is enough for the eyes.
Then it’s even simpler - we dig out a couple of strong magnets from the DVD (in the lens block), glue them to the laser. We try not to heat it too much when gluing with a heat gun.
We drill and saw square pipe blanks.
Holes Ф4mm with front side and on the other we drill out to 10mm
We screw it to the DVD-Yuka body.
Using rubber dampers from the DVD itself, we screw the linear drives to the body.
We get something like.....
We cut a strip of steel from the second DVD case and glue it to the horizontal linear module with a heat gun - as in the photo (we attach the laser to it using magnets)
On the lower drive, again using hot glue, we glue a piece of plexiglass/plastic 4mm thick and approximately 45x35mm in size. We glue the desktop to it using superglue with an activator. I cut it out of the body of an old 3.5" floppy
We try to glue the table strictly horizontally.
WITH reverse side We shoot a piece of plastic or plexiglass onto the rivets - we will attach the electronics to it with double-sided tape.
Yes, I almost forgot - I attached the linear modules to rubber bushings from some old printers - it is quite possible to use any suitable tubes - for example, cut an old felt-tip pen evenly.
So we got to the electronics. It's actually simple
Despite the fact that the nameplate says 12-36 volts, it should be powered with 12 volts.
If the motors spin in the opposite direction, simply turn off the power and turn the connector 180 degrees.
The connector has pinout AaBv (beginning of the first winding, end of the first winding, beginning of the second winding, end of the second winding)
The laser is powered and controlled by the 2003 chip. Only four outputs of the chip are used.
The program itself
(Mylaser.zip)
HEX firmware
(grbl_v0_8c_atmega328p_16mhz_9600.hex.rar)
Arduino firmware
(grbl-master.rar)
GRBL controller program
(GrblController361Setup.rar)
It is very important to upload the firmware to the Arduino with a bitrate of 9600. With a different bitrate, the program simply will not see the Arduino.
It is necessary to fill in the EEPROM with the “step per mm” values; steppers in SD/DVD ROMs usually have 20 steps per revolution. StepSticks usually use a multiplier of 1/16 - i.e. 320 steps. The drive usually travels 3mm per revolution (you need to measure the distance between the turns on the drive screw). 320/3 = 106 steps per 1 mm.
We enter this value using the command line in the GRBL Controller program
$100=106 (Enter)
$101=106 (Enter)
$102=106 (Enter)
You can upload the firmware to Arduino Uno using the Arduino program. way:
Unpacking the archive
Rename (for example, just to GRBL)
Copy to the "library" folder
Open the program, menu Sketch - load library - select GRBL.1421957319229.prev.jpg)
PS the workpiece is attached to the desktop using the same magnets from the DVD head
PPS laser focusing is done by raising/lowering the diode relative to the table. For this purpose we have provided a magnetic mount.
Attention! Be careful when using lasers. The laser used in this machine may cause vision damage and possibly blindness. When working with powerful lasers above 5 mW, always wear a pair of safety glasses designed to block the laser wavelength.
A laser engraver on Arduino is a device whose role is to engrave wood and other materials. Over the past 5 years, laser diodes have advanced, allowing fairly powerful engravers to be made without much of the complexity of operating laser tubes.
You should be careful when engraving other materials. So, for example, when used in working with laser device plastic will produce smoke which contains dangerous gases when burned.
In this lesson I will try to give some direction to the thought, and over time we will create more detailed lesson for the implementation of this complex device.
To begin with, I suggest you look at what the entire process of creating an engraver looked like for one radio amateur:
Strong stepper motors also require drivers to get the most out of them. In this project, a special stepper driver is used for each motor.
Below is some information about the selected components:
- Stepper motor – 2 pieces.
- Frame size is NEMA 23.
- Torque is 1.8 lb-ft at 255 oz.
- 200 steps/revolutions – 1 step 1.8 degrees.
- Current – up to 3.0 A.
- Weight – 1.05 kg.
- Bipolar 4-wire connection.
- Stepper driver – 2 pieces.
- Digital stepping drive.
- Chip.
- Output current – from 0.5 A to 5.6 A.
- Output current limiter – reduces the risk of motor overheating.
- Control signals: Step and Direction inputs.
- Pulse input frequency – up to 200 kHz.
- Supply voltage – 20 V – 50 V DC.
For each axis, the motor directly drives the ball screw through the motor connector. The motors are mounted on the frame using two aluminum corners and an aluminum plate. The aluminum corners and plate are 3mm thick and are strong enough to support a 1kg motor without bending.
Important! The motor shaft and ball screw must be properly aligned. The connectors that are used have some flexibility to compensate for minor errors, but if the alignment error is too large, they will not work!
Another process of creating this device can be seen in the video:
2. Materials and tools
Below is a table with the materials and tools needed for the project " laser engraver on Arduino."
| Paragraph | Provider | Quantity |
| NEMA 23 stepper motor + driver | eBay (seller: primopal_motor) | 2 |
| Diameter 16mm, pitch 5mm, ball screw 400mm long (Taiwanese) | eBay (seller: silvers-123) | 2 |
| 16mm BK12 support with ball screw (drive end) | eBay (seller: silvers-123) | 2 |
| 16mm BF12 Ball Screw Support (No Driven End) | eBay (seller: silvers-123) | 2 |
| 16 shaft 500 mm long | (seller: silvers-123) | 4 |
| (SK16) 16 shaft support (SK16) | (seller: silvers-123) | 8 |
| 16 linear bearing (SC16LUU) | eBay (seller: silvers-123) | 4 |
| eBay (seller: silvers-123) | 2 | |
| Shaft holder 12 mm (SK12) | (seller: silvers-123) | 2 |
| A4 size 4.5mm clear acrylic sheet | eBay (seller: acrylicsonline) | 4 |
| Aluminum Flat Rod 100mm x 300mm x 3mm | eBay (seller: willymetals) | 3 |
| 50mm x 50mm 2.1m Aluminum Fence | Any theme store | 3 |
| Aluminum Flat Rod | Any theme store | 1 |
| Aluminum corner | Any theme store | 1 |
| Aluminum corner 25mm x 25mm x 1m x 1.4mm | Any theme store | 1 |
| M5 socket head screws (various lengths) | boltsnutsscrewsonline.com | |
| M5 nuts | boltsnutsscrewsonline.com | |
| M5 washers | boltsnutsscrewsonline.com |
3. Development of the base and axes
The machine uses ball screws and linear bearings to control the position and movement of the X and Y axes.
Characteristics of ball screws and machine accessories:
- 16 mm ball screw, length – 400 mm-462 mm, including machined ends;
- pitch – 5 mm;
- C7 accuracy rating;
- BK12/BF12 ball joints.
Since the ball nut consists of ball bearings rolling in a track against a ball screw with very little friction, this means that motors can run at higher speeds without stopping.
The rotational orientation of the ball nut is locked using an aluminum element. The base plate is attached to two linear bearings and to a ball nut through an aluminum angle. Rotation of the Ballscrew shaft causes the base plate to move linearly.
4. Electronic component
The laser diode selected is a 1.5 W, 445 nm diode housed in a 12 mm package with a focusable glass lens. These can be found, pre-assembled, on eBay. Since it is a 445 nm laser, the light it produces is visible blue light.
The laser diode requires a heatsink when operating at high levels power. When constructing the engraver, two aluminum supports for SK12 12 mm are used, both for mounting and for cooling the laser module.
The output intensity of a laser depends on the current that passes through it. A diode by itself cannot regulate current, and if connected directly to a power source, it will increase current until it fails. Thus, an adjustable current circuit is required to protect the laser diode and control its brightness.
Another option for connecting the microcontroller and electronic parts:
5. Software
The Arduino sketch interprets each command block. There are several commands:
1 – move RIGHT one pixel FAST (blank pixel).
2 – move RIGHT one pixel SLOW (burnt pixel).
3 – Move LEFT one pixel FAST (blank pixel).
4 – Move LEFT one pixel SLOW (burnt pixel).
5 – move up one pixel FAST (empty pixel).
6 – Move UP one pixel SLOW (burnt pixel).
7 – Move DOWN one pixel FAST (blank pixel).
8 – move DOWN one pixel SLOW (burnt pixel).
9 – turn on the laser.
0 – turn off the laser.
r – return the axes to their original position.
With each character, the Arduino runs the corresponding function to write to the output pins.
Arduino controls engine speed through delays between step pulses. Ideally, the machine will run its motors at the same speed whether it is engraving an image or passing a blank pixel. However, due to the limited power of the laser diode, the machine must slow down at pixel records. That's why there is two speeds for each direction in the list of command symbols above.
A sketch of 3 programs for the Arduino laser engraver is below:
/* Stepper motor control program */ // constants won't change. Used here to set pin numbers: const int ledPin = 13; // the number of the LED pin const int OFF = 0; const int ON = 1; const int XmotorDIR = 5; const int XmotorPULSE = 2; const int YmotorDIR = 6; const int YmotorPULSE = 3; //half step delay for blank pixels - multiply by 8 (<8ms)
const unsigned int shortdelay = 936;
//half step delay for burnt pixels - multiply by 8 (<18ms)
const unsigned int longdelay = 2125;
//Scale factor
//Motor driver uses 200 steps per revolution
//Ballscrew pitch is 5mm. 200 steps/5mm, 1 step = 0.025mm
//const int scalefactor = 4; //full step
const int scalefactor = 8; //half step
const int LASER = 51;
// Variables that will change:
int ledState = LOW; // ledState used to set the LED
int counter = 0;
int a = 0;
int initialmode = 0;
int lasermode = 0;
long xpositioncount = 0;
long ypositioncount = 0;
//***********************************************************************************************************
//Initialisation Function
//***********************************************************************************************************
void setup()
{
// set the digital pin as output:
pinMode(ledPin, OUTPUT);
pinMode(LASER, OUTPUT);
for (a = 2; a <8; a++){
pinMode(a, OUTPUT);
}
a = 0;
setinitialmode();
digitalWrite (ledPin, ON);
delay(2000);
digitalWrite (ledPin, OFF);
// Turn the Serial Protocol ON
Serial.begin(9600);
}
//************************************************************************************************************
//Main loop
//************************************************************************************************************
void loop()
{
byte byteRead;
if (Serial.available()) {
/* read the most recent byte */
byteRead = Serial.read();
//You have to subtract "0" from the read Byte to convert from text to a number.
if (byteRead!="r"){
byteRead=byteRead-"0";
}
//Move motors
if(byteRead==1){
//Move right FAST
fastright();
}
if(byteRead==2){
//Move right SLOW
slowright();
}
if(byteRead==3){
//Move left FAST
fastleft();
}
if(byteRead==4){
//Move left SLOW
slowleft();
}
if(byteRead==5){
//Move up FAST
fastup();
}
if(byteRead==6){
//Move up SLOW
slowup();
}
if(byteRead==7){
//Move down FAST
fastdown();
}
if(byteRead==8){
//Move down SLOW
slowdown();
}
if(byteRead==9){
digitalWrite (LASER, ON);
}
if(byteRead==0){
digitalWrite (LASER, OFF);
}
if (byteRead=="r"){
//reset position
xresetposition();
yresetposition();
delay(1000);
}
}
}
//************************************************************************************************************
//Set initial mode
//************************************************************************************************************
void setinitialmode()
{
if (initialmode == 0){
digitalWrite (XmotorDIR, OFF);
digitalWrite (XmotorPULSE, OFF);
digitalWrite (YmotorDIR, OFF);
digitalWrite (YmotorPULSE, OFF);
digitalWrite (ledPin, OFF);
initialmode = 1;
}
}
//************************************************************************************************************
// Main Motor functions
//************************************************************************************************************
void fastright()
{
for (a=0; a
6. Launch and setup
Arduino represents the brain for the machine. It outputs the step and direction signals for the stepper drivers and the laser enable signal for the laser driver. In the current project, only 5 output pins are required to control the machine. It is important to remember that the bases for all components must be related to each other.
7. Functionality check
This circuit requires at least 10VDC power, and has a simple on/off input signal provided by the Arduino. The LM317T chip is a linear voltage regulator that is configured as a current regulator. The circuit includes a potentiometer that allows you to adjust the regulated current.
The time has come when the hyperboloid of engineer Garin from the novel by Alexei Tolstoy moved to the kitchen table of an ordinary Moscow apartment.
A couple of years ago, you could find inexpensive laser engraver sets in Chinese online stores. At first, the laser power was 100 mW, then 500 mW... Recently an engraver with a power of 5 W appeared, this power of a semiconductor laser already allows not only to burn pictures on plywood, but also to cut plywood.
The laser cutter assembly kit arrived in high-quality packaging. Polystyrene foam in a cardboard box.
The laser engraver 5500mw A5 Mini Laser Engraving Machine is supplied as a kit for assembly: aluminum guides, stepper motors, control board, glasses to protect eyes from laser radiation, housing parts for assembly and control board with fittings. It took one evening to assemble the device.
The design of a laser CNC is simpler than that of a 3D printer; the same guides along which stepper motors drive the head. Only the 3D printer has three of them, and they move the head in three dimensions. In our case, it is enough for the head to simply move along a plane in two dimensions. No force is needed to move it, since there is no mechanical contact with the workpiece material. The laser engraver connects to a computer via a standard USB port.
The part you want to cut out or the image you want to burn must be drawn in a vector program. The program must save the image file in wmf format.
A file in this format can be imported into the program that controls the engraver.
It is better to use the free SketchUp program for this (a fairly simple program for creating 3D models). The BenBox program that controls the engraver is downloaded free of charge from the seller’s website.
The laser power, unfortunately, is not adjustable. The program sets the speed of movement of the head - the faster it moves, the less it burns.
If you want to cut, set the speed lower. To regulate power, you need to order an additional board; Once installed, you can adjust the power manually. For engraving, 100-500 mW is enough and for cutting material - 2000-5000 mW.
The engraver smokes slightly during operation. With the window open, the smoke didn't bother me much. But smoke delays the laser beam, reducing its power and, accordingly, the cutting depth.
Everything would be fine, but laser cutting experts write that the lens can become smoky. Therefore, immediately after purchasing a machine, you need to make a powerful exhaust hood or at least install a fan on the engraver head.
HOW A LASER CNC MACHINE CUTS
As you know, a laser does not cut, it burns. The higher the laser power, the more resistant the material it can process. The essence of laser cutting is this. that the material has time to “evaporate” in the laser beam before the edges of the material adjacent to the cutting point begin to burn.
When cutting deep, the edges of the upper layers of the material burn, so a deep cut with a laser has a trapezoidal shape with the wide side on top. When cutting material with a weak laser, the edges of the material heat up and ignite. This can be combated by blowing a thin stream of air at the cut point and multiple passes along one and the other the same trajectory.
Only here there is not a linear relationship between laser power and number of passes. That is, if you can cut through a thin sheet of balsa or plywood with a 5W laser. then to make a cut with a 2 W laser you will have to make not 2-3 passes, but much more. So it’s better to give up hopes of “buying it cheaper and just driving along the cutting lines several times.” You need to take a more powerful laser, preferably with a power reserve.
LASER FOCUSING
Laser focusing is manual.
Place the object to be engraved.
When turning on the laser at minimum power, in order to focus it on the engraved object, you must manually rotate the adjustment of the focusing lens until the size of the spot turns into a point and becomes minimal. In this case we get maximum power.
When cutting plywood, the laser beam, having cut a couple of millimeters, is already out of focus, weakens and does not cut the plywood to the end. It turns out that the deeper we cut, the weaker the beam. In this case, it makes sense to focus the laser on the surface on which the plywood piece will lie.
Practical use of the engraver at home
The engraver is ideal for cutting leather. You can apply any design to the skin and immediately cut out patterns with a laser. The big advantage of a laser when cutting synthetic fabrics and leather is that the edges are burned and then do not become shaggy. Plastic is easy to engrave. You can make the cover of your favorite smartphone stylishly engraved.
Home Improvement Double Sided Tape Nano Clear No Trace Acrylic Magic...
In the previous article I described the experience of assembling and setting up an engraver from a Chinese kit. After working with the device, I realized that it would not be out of place in my laboratory. The task has been set, I will solve it.
There are two solutions on the horizon - ordering a kit in China and developing your own design.
DESIGN DISADVANTAGES WITH ALIEXPRESS
As I wrote in the previous article, the set turned out to be quite functional. The practice of working with the machine revealed the following design flaws:
- The design of the carriage is poorly designed. This is clearly visible in the video in the previous article.
- The rollers of the moving units are mounted on the panels with M5 screws and are connected to the panel on only one side. At the same time, no matter how you tighten the screws, there remains some play.
PLASTIC PARTS
Since the frame made from a machine-made profile is quite decent, it was possible to eliminate the identified shortcomings by recycling the plastic parts.
I described the laser holder quite well in. I also added an additional piece to the design that connects all four rollers on the right and left panels. This detail made it possible to eliminate play when moving panels.
All parts have fairly simple shapes and do not require supports or other difficulties when printing.
To order a set of plastic parts, you need to go to the online store:
Models of plastic parts for printing are available:
DEMONSTRATION OF WORK
The engraver's work and appearance can be assessed in the following video.
ENGRAVER CONSTRUCTION
The frame of the engraver is built on a machine-made aluminum profile 20x40. The parts supporting the moving parts of the engraver are made on a 3D printer. The moving parts move on standard rollers. The carriage carrying the laser module allows you to adjust the height of the laser above the desktop, which allows you to focus the power of the laser beam in a fairly large range.
The assembly of the structure is shown in 3D PDF format.
ASSEMBLY
The design is very simple. For this reason, assembly will not take much time and pain if you follow the recommended assembly sequence.
STEP 1. FRAMEWORK
As described above, the frame is constructed from 20x40 structural profile. Internal corners are used to twist the profile together.
On longer parts, threads are cut in the central holes of the ends for mounting legs and side panels (on the middle length).
The frame is twisted at the corners, with short parts inward. At this stage, you should not fully tighten the screws - it is better to do this after installing the legs.
The legs are attached with screws at four points. This is done so that the frame is assembled without possible distortions.
First you need to secure all four legs, again without fully tightening the fasteners.
Now you need to find the most flat surface possible! Arrange all the parts so that the frame “stands” tightly, without playing on the surface.
We stretch all the fasteners, starting from the inner corners and controlling possible distortions with a square.
STEP 2. RIGHT PANEL
Before assembling the right panel, a flexible coupling must be installed on the motor shaft.
Then you need to screw the stepper motor through a plastic spacer.
The position of the cable outlet and the spacer are clearly visible in the figure below.
STEP 3. LEFT PANEL
To assemble the left panel, you only need to press the bearing into the hole.
I tried to eliminate the gluing operation. To do this, he “sent a wave” along the surface of the hole for installing the bearing. For this reason, it is necessary to press the bearing firmly.
STEP 4. INSTALLATION OF THE LEFT PANEL
Then install the assembly on the profile.
And secure the lower rollers. The figure clearly shows that the mounting holes of the screws for fastening the rollers have a stroke of several millimeters. This is done so that the upper and lower rollers can be tightly tightened on the profile, eliminating play. The only thing is that you need to act carefully and not overtighten. In this case, the stepper motor will require excessive force to move the panels.
STEP 5. INSTALLING THE RIGHT PANEL
The following parts are required for installation.
First you need to install the top rollers.
Then install the assembly on the profile and install the lower rollers. Further installation is identical to the installation of the left panel.
After tightening the screws, you will need to check the progress of the panel. It should move quite easily and there should be no play.
STEP 6. INSTALLING THE GUIDE CARRIAGE
This design uses both panels to transmit movement along the Y axis. In order not to use 2 stepper motors, torque is transmitted to the left panel through a shaft with a diameter of 5 mm. After preparing the details, we begin.
First, the coupling shaft is installed and clamped with the flexible coupling locking screws.
During installation, it is necessary to ensure that the pulleys are not forgotten. There is no need to rigidly fasten them at the moment. Adjustment will be required when tightening the belts.
STEP 7. CARRIAGE
The carriage assembly is discussed in detail in the previous article...
Assembly is not particularly difficult.
STEP 8. INSTALLING THE CARRIAGE ON THE RAIL
First you need to collect all the necessary parts.
All installation operations are identical to the panel installation operations.
STEP 9. INSTALLATION OF BELTS
The belts are tightened with screws under the profile nuts. You will need to cut 3 straps in place and prepare the fasteners.
To begin with, the edge of the belt is located in the profile niche with the tooth down. After this, the nut is installed. It will take some force to install the nut.
When tensioning the belt, you will need to set the position of the pulley. The pulley is positioned so that throughout the entire run the belt rubs against the side edges of the pulley as little as possible.
To install the guide carriage belt, it is better to lift it as shown in the figure below, since it is still better to install the nuts into the niche from the end.
Afterwards the guide is lowered to its normal place.
Before tightening the second “tail” of the belt, you must make sure that the belt is tensioned sufficiently.
This completes the assembly of mechanics.
CONTROLLER
I plan to prepare a description of the controllers for controlling the engraver in a separate article. Follow the publications!
ASSEMBLY KIT AND TURNKEY LASER ENGRAVER
Since December 2017, I have been accepting orders for a complete assembly kit and an assembled, configured and completely ready-to-use laser engraver described in the article. Information is available in the online store.
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