Lab Box: Electrochemical Maching and 3D Printing

grabcad

Watch on YouTube https://www.youtube.com/watch?v=DINs7eMw7IQUpdate Video https://www.youtube.com/watch?v=N7VYreT1PGcNote: All printed parts may fit in a 120 mm cubic build volume. I printed all parts in PETG at 0.2 or 0.32 mm layer heights with 30% infill with 4 shells. I recommend printing out ~8 mm holes for the linear rods and testing what the tolerance of your printer is. You will need to cut several pieces of 8 mm linear rod, and 2020 aluminium extrusions for this printer. ALL STEP FILES AND FUSION FILES ARE ATTACHED BELLOW. Note: I have included in the step files plans for a d-sub connector, that way you do not have to keep attaching and unattaching wires to the motherboard. Just unplug the connector. Likes to the D-SUB connectors are bellow. Note: Gcode for metal cutting was produced using inkscape with the laser plugin. The start and end gcode was inserted. 100 passes were used at 10 mm/s. Best results were achieved when after each pass the z-axis was lowered .025 microns. To do this use inkscape to insert .1 mm decreases, then open the resulting file and find-replace with the new height. In 2005, researchers at the University of Bath took it upon themselves to develop the first low-cost 3D printers in the RepRap project. The goal of the project was hinted at in the name, to build a machine which could replicate rapidly, “rep rap”. Many components of their first prototypes were 3D printed out of thermoplastics. Since then, desktop, affordable, and open source thermoplastic 3D printer have come leaps and bounds. Today, they are safe, cheap, and produce relatively high cost components for only dollars in a few hours of time. However, every other essential component of 3D printer remain impossible for desktop machines to duplicate. These include stepper motors, machined aluminium brackets, hotends, nozzles, lead screws, extruders, and fasteners. All these components require the machining of multiple varieties of metal. Here we are putting forward a new affordable solution to problem of metal machining in a DIY/desktop environment, which uses already existing 3D printing infrastructure. Previously, there existed no simple and effective way to mill/machine/lathe metal on desktop 3D printers. Current attempts include the printing of green parts for sintering, lost-PLA casting, and the drastic augmentation of 3D printers with spindle motors for cutting and milling. Of particular interest is CNC milling on 3D printers using spindles. However, these motors are extremely loud, require aggressively engineered and rigid machines, and are expensive. In addition, the challenges of milling changes with the specific material. Commonly, metals such as titanium, tungsten, and other useful engineering materials are out of reach. Accuracy is also difficult to achieve on desktop machines. 3D Print is such a wonderful technology because it expands the freedom of its user. Imagine if that freedom included the ability to produce metal parts on only slightly modified 3D printers. Here we are putting forward a new solution to problem of metal machining in a DIY/desktop environment. Electrochemical machining (ECM) is a process where by a metallic workpiece is dissolved selectively using using an electrolyte and electrical current. Electrical current is applied to a workpiece (anode/negative), and a toolpiece (cathode/positive). A conductive solution of salt water, or similar solution, is flowed between the two. As the current passes, in the area between the work and tool piece, material is dissolved away from the workpiece. This metal, in the form of an oxide or hydroxide is then washed away. The advantage of this process is that no physical stresses or forces are applied to the machine performing the process. While milling requires extremely rigid machines with high torque motors, ECM can be done using any common 3d printer. The process is also completely silent, and can be done at home or in the office. The process may also operate using 12 volt systems at as little as 300 mA by out testing. Nearly any metal can be machined as well: Aluminium, steal, copper, silver, titanium, ect. Hardness and thermal properties have no effect on the process.2. How does ECM Work? Electrochemical machining is simply targeted rusting. Consider what happens if a piece of iron is left out in salt water. Over time, the metals surface will start to rust. This rust will weaken the outer structure of the metal, until bits and pieces start to flake off as red iron oxide. This process continues until the entire object of iron is a pile of red dust. Imagine if you could control what parts of the iron object were able to rust. Over time, only those sections of the object would flake off, and begin to fall apart. When you were done, every unwanted part of the tool piece would be removed. Electrochemical machining is very similar to this thought experiment. However, the process is accelerated by the same method it is controlled. The workpiece is the metal stock to be machined. It is connected to positive 12 volts. Another piece of metal, called the work piece, is connected to ground. The two pieces of metal, called electrodes are brought into very close proximity, so that the distance between them is minimal. Between the space remaining is flowed a very concentrated solution of electrolyte, which conducts electricity. This may contain sodium chloride (salt), sodium nitrite, or several other chemicals. Electricity will take the quickest path between the two electrodes, and electrons will flow from the cathode (negative) to the anode (positive). This is from the workpiece, through the electrolyte, to the toolpeice. At the cathode (toolpiece), electrons are used to split water into hydrogen gas (H2) and hydroxide ions (HO-). This is called reduction. These hydroxide ions are very reactive, and are an extremely strong base. At the anode (workpeice) iron has electrons removed from it, forming Fe3+ ions, which are also reactive. This is called oxidation. The hydroxide ions (HO-) react with the Fe3+ ions to form iron hydroxide, which decomposes with time to iron oxide. The surface of the workpiece is oxidized, forming metal hydroxides or oxides which are washed away. The greater the electrical current (electron flow), the greater the rate of reduction and oxidation at each electrode, thus the more material that will be removed. This allows for the process to be controlled. Other metals aside from iron may be used too, including aluminium.Reference Models BLTouch BLTouchE3D Reference Model E3D v6 HotendFans were taken from the Creality Ender 3 Model Parts Used 12 Volt Power Supply https://www.amazon.com/gp/product/B07MCVYGC4/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1Bltouch https://www.amazon.com/gp/product/B076PQG1FF/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1Bowden Tubinghttps://www.amazon.com/gp/product/B07FPJHRTQ/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1MKS SGEN L with TMC2209 Drivers https://www.amazon.com/gp/product/B0814V5K8J/ref=ppx_yo_dt_b_asin_title_o08_s00?ie=UTF8&psc=1Linear rods (Must be cut to size by hand) https://www.amazon.com/gp/product/B01LXAZFKZ/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1https://www.amazon.com/gp/product/B07DPGD69D/ref=ppx_yo_dt_b_asin_title_o08_s00?ie=UTF8&psc=1https://www.amazon.com/gp/product/B07SKMBKWJ/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=12020 Aluminium (Must be cut to size by hand) https://www.amazon.com/gp/product/B07F6R2Z99/ref=ppx_yo_dt_b_asin_title_o07_s00?ie=UTF8&psc=1Part Cooling Fan https://www.amazon.com/gp/product/B07JKVNMY3/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&psc=1Fasteners https://www.amazon.com/gp/product/B07CJ7PSS9/ref=ppx_yo_dt_b_asin_title_o06_s01?ie=UTF8&psc=1https://www.amazon.com/gp/product/B07KSC3TX1/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1https://www.amazon.com/gp/product/B07VNDFYNQ/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1Bushings https://www.amazon.com/gp/product/B06XPRCMJS/ref=ppx_yo_dt_b_asin_title_o05_s00?ie=UTF8&psc=1Belts and Idlers https://www.amazon.com/gp/product/B07JKT5BZQ/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1Endstops https://www.amazon.com/gp/product/B06XTB7WMK/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1Threaded Inserts (For Hotend Mount and Endstops) https://www.amazon.com/gp/product/B01IYWTCWW/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1Couplers https://www.amazon.com/gp/product/B01HBPHSII/ref=ppx_yo_dt_b_asin_title_o04_s02?ie=UTF8&psc=1Regulators (For ECM Autobed Leveling) https://www.amazon.com/gp/product/B06XZ1DKF2/ref=ppx_yo_dt_b_asin_title_o05_s00?ie=UTF8&psc=1D-SUB Connectors https://www.amazon.com/gp/product/B07C6W5TJ9/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1