"Aiban.com successfully held an offline 3D printing experience exchange party on the Tanabata Festival on August 2. If you want to see the details of our party, please move to the full record of aiban.com's 3D printing experience exchange meeting (many pictures have beautiful women). If you want to print the drawn 3D model, welcome to our activity 3D printing design material collection - you design, I print!
At present, 3D printing technology has been warmly pursued by the media and the public. It is considered as a major breakthrough in the field of manufacturing technology in the world in the past 20 years and "will promote a new industrial revolution together with other digital production modes". In short, 3D printing is a rapid prototyping technology, which constructs objects by printing layer by layer based on digital model files and using bondable materials such as powder metal or plastic.
3D printing technology was promoted and developed in the 1980s, but the price has been high due to patent protection. Now many core patents of 3D printing are about to expire, such as laser sintering, which can realize the bonding of high melting point metals and ceramics. The expiration of these core patents will bring an explosion in the market, the price of relevant equipment will drop sharply, and more and more companies will enter the field of 3D printing. It is estimated that by 2016, the domestic 3D printing market will reach 10 billion yuan, even surpassing the United States. 3D printing technology can be integrated into various industries as a basic manufacturing technology, so the market prospect is very broad.
At present, there are many desktop 3D printers with different prices on the market, and 3D printing is also promising in consumer applications. Thanks to the expiration of the patented technology of fused deposition molding (FDM) (realizing the printing of hot-melt materials), a large number of open-source 3D printers have emerged, making 3D printing gradually enter the eyes of ordinary people. The Ormerod 3D printer to be introduced today is such an FDM open source printer. It is manufactured by reprappro, which is the first company to manufacture open source 3D printers. Ormerod is actually named after an entomologist. The Ormerod 3D printer is completely open source. The finished product is packaged in the form of parts, which is convenient for transportation. The buyer needs to assemble it by himself, and the process is not complex. Interestingly, Ormerod provides 3D models of plastic parts, which you can use to print your own Ormerod.
Thanks to eurotime Electronics (RS) for providing us with Ormerod, we can personally experience the magic of 3D printing technology. At present, you can directly purchase the Ormerod 3D printer through the RS website, with a price of about 4000 yuan. We got a limited edition red Ormerod, which has been fully assembled.
If you buy from RS website, you need to assemble by yourself. The assembly process is not complicated. There is a detailed installation manual on reprappro website. If e is really bad, there are translated Chinese documents in the designspark community. The installation manual is very detailed. You can assemble by yourself with simple tools, which is also a spirit advocated by open source hardware. You enjoy DIY in the process of assembling by yourself.
Hardware construction
Generally speaking, desktop printers use FDM technology. One reason is that there is no patent fee and the cost is greatly reduced. Different from the desktop printer with tens of thousands of yuan, the price of Ormerod is lower. The basic structure and principle of FDM printer are similar, so Ormerod is very suitable for learning and entertainment as an entry-level 3D printer. Let's take a closer look at this Ormerod 3D printer.
Many parts of Ormerod are plastic products, which is due to cost considerations. Reprappro discloses the 3D models of all parts. We can copy an Ormerod with a 3D printer. It's very creative. The Red Limited Edition is very beautiful. The open architecture allows us to study the structure of 3D printer in detail.
X-axis motor
The overall size of the printer is 500x460x410mm, and its printable area is 200x200x200mm. Objects beyond this range cannot be printed. Important indicators of 3D printer include printing volume, speed, accuracy, resolution and deposition speed. The higher these indicators, the more expensive they are. The printing speed of Ormerod is up to 1800mm / min. Its accuracy reaches 0.1mm, which refers to the positioning accuracy of the nozzle in the horizontal plane; The resolution bit is 0.0125mm, and the resolution refers to the degree that the motor rotates one circle to drive printing; Therefore, the resolution is generally higher than the accuracy, because the positioning of the nozzle will be affected by other factors, such as the quality of gear tape.
The inspiration of the 3D printer comes from the inkjet printer. If the inkjet printer is driven by a motor to draw on a two-dimensional plane, the 3D printer is composed in a three-dimensional space. Its main movement is driven by stepping motors in three directions of X, y and Z axes.
Y-axis direction stepping control motor, the red wire is connected with the limit block microswitch
Z-axis stepping motor and lifting rod
10. There is a pallet workbench in the Y direction. We print the real object on this pallet. The tray has a heating function, which is to make the object base more stable when printing（ (next page)
To solve the problem of controlling the movement of the motor, what is the next step? The secret is on the nozzle. The nozzle has a heating function. After heating, the plastic materials can continuously overflow from the nozzle by gravity and continuous feeding and extrusion. These melted plastics with a diameter of about 0.5mm "print" new items with the change of nozzle position. Ormerod supports PLA and ABS materials with different melting points, so the nozzle must be heated to the corresponding temperature before printing. Of course, there is a cooling fan at the nozzle. Another point to mention is that Ormerod is a monochrome 3D printer, which does not support color mixing function at present.
Nozzle, heating block and cooling fan
In addition to the nozzle spraying materials, we also need to supply raw materials automatically in order to print continuously. Here, an automatic feeding module is controlled by a stepping motor. Generally, 3D printing materials are rolled, so they can be continuously added to the nozzle through the automatic feeding device. Here we know that Ormerod controls the position of the nozzle and the ejected material by accurately controlling four stepping motors. Its principle is so simple!
Feeding part motor of printer
Drum mounted PLA printing material, red, diameter 1.75mm
The main control board of the printer is very important. Will it be very complex? On the side of the printer, you can see the main control board duet of Ormerod, which is also an open source development board. Duet is not complex. It is equivalent to a variant of Arduino due development board. It is compatible with Arduino due. The main control chip is a 32-bit ARM core processor sam3x8e. Duet is more powerful than the 8-bit Arduino development board. It can control the drive of up to 8-way stepping motor. The built-in Ethernet interface enables the 3D printer to be controlled through the network, and supports USB and SD interfaces at the same time. The best thing is that duet is also open source. You can download all software and hardware materials on the Internet.
Duet of main control board, compatible with Arduino due
Duet wiring diagram
The power supply of the main control board only needs 5V, but we know that there are heating parts and motor control on the printer, so 12V power supply is needed. Here we use a standard ATX chassis power supply, which can provide the power required by Ormerod.
ATX power interface
The above is the main part of the hardware structure of Ormerod. Another important thing is to zero the positioning of the X, y and Z axes, because to accurately control the nozzle positioning, it is necessary to accurately locate the positions of the three axes（ (next page)
Ormerod uses three different zeroing methods in three directions
In the y-axis direction, there is a limit block microswitch here. When the y-axis moves here, the main control board will know that the y-axis has reached the maximum position.
In the x-axis direction, the limit block is not used here, but is positioned by the distance sensor. The distance sensor is installed on the nozzle module. When it moves to the zero point of x-axis, the position of x-axis is known through the sensor main control board.
The zeroing of Z axis is a little troublesome. It adopts infrared reflection sensor. A small piece of aluminum foil is pasted on the edge of the bottom plate. Positioning the z-axis is to calculate a voltage value through the reflected current of the sensor, so as to determine the position on the z-axis.
sensor
An important step before starting printing is zeroing and compensation in three axis directions, which is omitted here.
Software part
After understanding the hardware part, we need to prepare to download some software and documents to use the 3D printer:
Arduinide - used as USB driver of equipment and communication debugging
Reprap firmware - this software is used to control the hardware function of duet board
Pronterface -- communicate and control the printer through USB
Google Chrome - control duet board through network interface
Slic3r -- used to convert 3D files into gcode format files
Ormerod files - configuration file of slic3r
The underlying control software pronterface can control the gcode instruction and convert the gcode instruction into the instruction to control the stepper motor for execution; In the interaction layer, STL format is transformed into gcode instructions that can be recognized by the machine through slic3r software; At the top layer, we need modeling software to get the 3D model, such as AutoCAD, SOLIDWORK, designspark mechanical, etc., and output STL format files. Through such a process, we convert the 3D model into a real object.
Little knowledge
STL Format: in computer graphics application system, a file format used to represent triangular meshes. Its file format is very simple and widely used. STL is the standard file type used by most rapid prototyping systems. STL uses triangular meshes to represent 3D CAD models.
Gcode: an instruction language for automatic machine control, which is commonly used in CNC machine tools, laser engraving, etc.
The Ormerod main control board has two communication interfaces: USB and Ethernet. Printing can be controlled through either USB serial (pronterface) or Ethernet (Google Chrome). Some configuration files and gcode instances are stored in the SD card, which can print faster through the SD card. The contents of the SD card can be found in reprappro firmware.
USB interface, Ethernet card, SD card slot
When we are ready, let's actually operate 3D printing. First try the driver of the main control board and connect USB to the computer. ATX power supply is not required at this time. Open the Arduino ide software to view the driver of the main control board. The Arduino IDE is mainly used for driver installation and communication debugging. After the driver is successfully installed, open the serial port monitor of IDE and enter M115 to see the firmware version number, indicating that the communication is normal.
You can also enter m503 to check whether SD card reading is normal.
Next, we will never use the Arduino ide to close the software（ (next page)
Open the pronterface software and connect the serial port communication. The content of the interface of pronterface is very rich. You can enter gcode command control and view the working information of many 3D printers.
Pronterface software interface
After the communication is normal, the ATX power can be connected below. We can set the temperature of the nozzle or workbench to see if the heating function is normal. You can also input commands to control the movement in the X, y and Z axes.
For example, if you enter "G1 X10 F200", the x-axis direction should move to 10mm at a speed of 200mm / min. You can also click the graphical arrow on the right to move the nozzle position.
Test the direction movement of X, y and Z axes
Some debugging may be required before formal printing, such as zero setting of X and Y axes, compensation of Z axis, speed control of extrusion material motor, etc. Through these debugging, the machine can run more accurately. If you are interested, please refer to the installation manual.
The SD card stores some test gcode files. We can also copy the generated gcode files to SD for operation. The printing speed of the files through the SD card is faster. The material we use this time is PLA. First, set the nozzle temperature of 200 ° and the workbench temperature of 57 ° (reference value). After heating, we can start printing now.
Print the test file ormaxis. G
Select SD print test file ormaxis. G in the interface of pronterface, and the 3D printer will start to work automatically.
Print test file
To print your own model, you must first output STL format files through 3D modeling software. Interestingly, Ormerod provides 3D models of all plastic parts, which can be downloaded online.
Slic3r software interface, an STL file has been loaded
3D view of STL file
After obtaining the STL file, we can slice it through slic3r software to generate gcode file, so that we can print our own design. Slic3r has many configuration parameters. Fortunately, Ormerod provides slic3r configuration file, which is easier to use.
Summary
This paper introduces a cost-effective open source 3D printer provided by rs. As an entry-level desktop 3D printer, Ormerod is very suitable for work and entertainment. By studying the hardware structure and software operation, we deeply understand the working principle of 3D printer. Ormerod is completely open source. All software and hardware data can be downloaded from the Internet. Its printing range is 200x200x200mm. It is suitable for making some small parts and design models. At present, the price is only more than 4000 yuan, which is a good reference for users who want to experience 3D printing and research.
reference material
Free 3D modeling software
Reprappro Ormerod assembly and commissioning document summary
Reprappro Ormerod website
Ormerod software data
Compatible with duet data of Arduino due main control board
Original statement: This article is original by Aiban. Reprint is declined“
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