Instructables 3d printer. To calculate the sampling rate of the 3D printed record I used the following relationship: sampling frequency = (resolution per inch)* (inches per revolution)* (revolutions per second) in order to maximize the sampling frequency, I want all of these numbers (res/inch, inch/rev, rev/sec) to be as high as possible. Instructables 3d printer

 
 To calculate the sampling rate of the 3D printed record I used the following relationship: sampling frequency = (resolution per inch)* (inches per revolution)* (revolutions per second) in order to maximize the sampling frequency, I want all of these numbers (res/inch, inch/rev, rev/sec) to be as high as possibleInstructables 3d printer  This library allows you to save 3D geometries in the STL file format, STL files that form a watertight mesh can be printed by a 3D printer

The process for molding paper into solid 3D forms is as follows: Blend the paper into a pulp with water. It's also relatively compact with easy-to-use software. In the pictures above you can see the base for the x-axis sliding table (first and second pictures), the mechanism which will make the x-axis table translate left and right (third picture), and the table itself (last two pictures). But the Bowden system can cause severe trouble in 3D printing, such as jammed filament. line count: 4. It's also the step where you need to pay attention to what you're doing as you could seriously injure yourself and/or ruin your printer modification completely. Get printing and bring your visions to life! 3D Printer - Instructables 3D Printer By Alex-VL in Workshop 3D Printing 3,804 62 Favorite EWaste 60$ 3DPrinter by mikelllc in 3D Printing How to Calibrate the Extruder on Your 3d Printer by 527666229 in 3D Printing Delta Bot: DIY 3D Printer by Danny Lu in 3D Printing A Low Cost 3D Printer With Basic Tools by hschlech in 3D Printing 8 years ago. The other discs are 3D printed in green ABS-like material and transparent "Vero clear" plastic. Printables; Basics; Buyer's Guides; News; Reviews; Get It 3D Printed. Updated Apr 20, 2023. It originated as the Mendel, then the Prusa Mendel, and is now in the form of the Prusa i3. Board circuit 3d printed potential developing lots. Learn how to start with a 3D model template, perform some basic modifications, and print your customized project. Read on for some cool (partially) 3D printed mouse projects! All3DP; All3DP Pro; Pro . You could buy thicker (1/4") sheet, but it's more expensive, and probably vastly more difficult to cut. 3D Printed Electronics 2023: Market Study & Forecast. Compatible Track radius: Min 300mm. ) Trim excess construction lines. It uses a Raspberry Pi computer for the brains, a Raspberry Pi RP2040 based microcontroller to control the movement, and the Raspberry Pi Hi Quality camera as the telescope. On your printer's controller board very little changes. Step 1: CNC Hardware Setup - Items. In fact, there have been some 3D printing. Create a Custom Candy Mold. This takes account for the thickness of the paper. Unscrew the z-axis from the base of the 3D printer. Step 5: Add Filament Feedthroughs. When you print the parts, align the parts so they match the corresponding image at the top of the page for the best results I have found. 1mm or 0. "Hairline" line thickness adjustment for Epilog lasers. STL files from Autodesk Inventor's file type . Download. Solar System Orrery (3D Printed) Heat Exchangers and 3D Printing. There are three screw holes for fixing this component to the table. Tagged with: diy 3d printer • EV3 • hot glue gun printing • instructables • lego • lego 3D printer • legos. Just to test, insert the four flags into the appropriate holes in. com. Tell us about yourself!. This (readable) SVG file contains all lines which are required to create this. Recent News. Be sure to add supports everywhere on the vine and pumpkin base when you slice those files. After all the components are in place, the next step is to attach the hot glue gun internal. Put in linear bearings to the bearings holder and put them on shafts. Since you'll be working with the mains voltage you need to be really careful. Meet the 2nd Generation X-Carve. Continue with Apple. To kick off this project, we will need to open up the Ender 3 control box to expose the controller board inside. Cut 2 pieces of 1mm diameter iron wire, 54mm long and two 52mm long. Source: sharathnaik via Instructables. Using the Customizable Lithopane thing on Thingiverse. 3. for 365 days, only $2. awt. 2. Step 4: Clamp Set-up Blocks for Parallel or Bar Clamps. 2021 - Découvrez le tableau "Logiciel cnc" de Dominique Willefert sur Pinterest. . 1 part of silica sand. A simple Philips screw driver is all that is needed to take apart most of the printers. The Best 3D Printer Auto-Bed Leveling Sensors of 2023. Already a subscriber? Continue with the provider and email address you used when you subscribed. Step 2: Making the Parts Ready to Print. 1- A circuit board is designed and printed on a PLA filament printer, in this case it was a MakerBot Replicator 2. Make sure it lines up with the stand-offs, and that the ON/OFF switch works. Collections. This is a list of the things that are mostly necessary for the hardware setup: Gantry - Alas, an important aspect to building a 3d printer is acquiring a gantry! We used a modified. 99) Elegoo Saturn 2 MSLA 3D Printer — $299. Learn how to get the best print possible from your 3D models on Instructables. Step 1: Let's Get This Out of the Way: Ads! Pro! Steps! Instructables is ad supported — there are ads, lots of. 5W - 3D Printed. Step 1: Printing. 10. By mounting the filament spool holder to the side; the footprint of the printer is unnecessarily huge. Favorite. You can for instance use a winding system or. Discussions. The inserts will then be used to screw the arms that will hold the hexagons together. instructables Wiring 3D Printer RAMPS 1. Put one extra layer of. A 3D printer deposits little drops/line of molten plastic from a headed tip (nozzle). ) 3. Click on "Fetch Frame" and make sure that the blue horizontal line touches the top of the turning table and the yellow horizontal line touches the bottom of the turning table. The 3D box design must be saved to a SVG file. stl" and "Nut. Printing Services. A dual head 3D printer capable of printing with model and soluble support material would be ideal, but not required. This Instructable links to a video showing the steps I took to design, 3D print clean and assemble a simple 6mm by 1 threaded nut and bolt. Welcome to the world of 3D printing! In this class, you will learn everything you need to know to design and 3D print your own creations. Start to build your base plate by striking a 3 point arc across the bottom face of the mesh. 3D printers have a wide. Remember about the angle of 90 degrees ! Cut the linear rail shafts to 620mm. The internet is a wonderful place for 3D printing. In the press. Make sure your pocket hole jig is set to 3/4", the thickness of the desktop. The next step is where you roll up your sleeves and start the cutting and modifying process. The first step is to build the x-axis. Printing QR codes can be very useful for a variety of different purposes. 3x faster, more rigid, and more accurate than the original X-Carve. Again this can easyly be fixed with memento. Rhombic Dodecahedron Infinity Lamp. COVID 19 Healthcare Workers Protection Glasses: Hello everybody! This is a call for help to anybody owning a 3D printer! My wife and I are both doctors and both working in hospitals. 2. First, using your heat gun, warm up the hexagonal hole on one side of the belt tensioner 3D printed part. (To 3D print the hand you will need to download the . Feb 5, 2022 - Explore Rohit Iyer's board "Tools & Tool Mods" on Pinterest. Just a couple comments for others if picking up these models. Categories: Price: Cost of base model in USD. Makes assembly and gluing a lot easier. First we open up tinkercad and grab a round roof you can search round roof but it should be there by default. (We also used a modified version of his code. Step 3: Removing the Print Head Assembly. Dec 28, 2016The Instructables page provides thorough instructions for everything from soldering the cables to the motors and doing the basic electrical work, installing and using Arduino printer control. Quantum Computer. Instructables — Free 3D Printer files with great guides. The first type of printer is the most common style of 3D-printer. Instructables user utilizes 3d printing to etch copper circuit boards. Roll the brayer in the ink and keep rolling it up and down until the ink is tacky and small peaks form (see photo). The old lost-and-found was a drawer in the corner, and we need…16. Make your own 3D printer filament ! Cheap and high quality at a decent speed of 150-190 IPM ! (4-5 meters per minute) UPDATE: Now with wiring diagram ! Long read: 3D printers are cool and they finally start to drop in price. Have the partner slowly depress the heel to the bottom of the clay. Step 1: How It Works. This $500. 7 Comments. Connect the black wire from the 9V battery snap to the ground pin on the Arduino socket and the red wire to the V-in pin. Start by orienting the lens so that the frame will have a consistent curvature around your face. This is clearly not a fast robot, as the targets are simplicity and cost effectiveness. 12 Favorite 3D 3D Scanning Yourself in High Resolution With a Camera by shuang peng in 3D Printing How to Make a Metal Key With a 3D Printer by Proto G in 3D Printing A. Download files and build them with your 3D printer, laser cutter, or CNC. Bekijk meer ideeën over prints, printer, grappige mode. Engineering your own orthotics products can be fun and undoubtedly useful for the health industry. Screw Y shafts holder to the frame. Draw a curve, tracing the top surface, that extends passed the lens and is tangent at your center line. Aluminum block method: Drill holes in an aluminum block to clamp the filament ends. Summary Make your own Levitating Planter! I found a kickstarter for a product called "LYFE" and I loved the design. Step 6: Attach Motors. 2. Instructables. Step 3: #define MOTHERBOARD " (Your Motherboard From Boards. The process for molding paper into solid 3D forms is as follows: Blend the paper into a pulp with water. But do not insert the rear panel in the anterior cabinet. All3DP; All3DP Pro; Pro . Step 3: Importing the Moai File Into Tinkercad. Well here is a great use. If you want to there is a thing you can do once it starts you can turn up the printers “FR” or feed rate by going to the info screen (the screen that appears when you turn on the printer) and turning the knob to. Then attach glue gun head to the previously put-together extruder parts. Retro Records. Triangular shapes pasted with sponge gourd seeds for ear rings. 99. Use washers to protect the printed part. Using a ruler or calipers measure up 120mm from the top of the extruder idler and place a mark on the filament. Use it to cut flexible circuit board material larger than the pattern. WORD OF MOUTH: Invite your friends to come, discover the platform and the magnificent 3D files shared by the community! Cults. Sierra Space’s New Engine Uses Agile Space’s 3D Printed Preburner for Better Propulsion. Bathroom 3D printing ideas. The project uses Arduino UNO, four standard servos, two micro servos, eight push buttons, an LED, and resistors. I test fit a roll to find the natural unspooling level of the filament, and drilled more holes to accommodate the filament feeders, which also get o-rings before being tightened and fitted with a piece of teflon tubing, which keeps dust and air off the filament on its way to the printer. Updated Oct 24, 2023. Each leg is oriented differently so pay close attention to which 3D printed parts you use for each leg. The motor windings have three connections (a brushed motor will have only two)Use small pins (pegs) to hold it in place but let the printer move smoothly. Limits switches or 'end stops' as they are known to the 3D printing community can be troublesome for Hobby CNC and 3D print setups. 3D Printing: Make a project using a CNC machine or 3D printer by: Instructables: 21 Prizes: 2022. ) on panel B, then mount the 608ZZ on the top panel C and the two ø8 bars, checking that they are vertical and parallel to each other. The 6 3D printed parts for each leg: link 1, link 2, link 3, link 4, foot, servo carriage; 3 x servo; 25T servo horn Step 1: Building the Frame. Step 2: Cutting the Power. A "working curve" describes the thickness to which a resin cures as a function of the light "dose" for a given light source. Ability to quickly configure slotted internal divisions, both X and Y. It would later help to insert each part into the gap. The printing time is very short since the model is not so big, It took me less than 40 minutes to get all the parts 3d printed, As no supports or rafts were used there is no need for post-processing also known as cleaning. ; End Cap - Used on the edges of each divider as needed to make a snug fit in the drawer. In recent months I've started to realize the benefits of owning a 3D printer and have used it to print replacement parts for sewing machines, vintage electronics, espresso machines, and my benchtop CNC router. MIKE80 says:Step 2: Exposure Time (s) The print quality for each 3D resin is also affected by the light power and the curing or exposure time. Push in the pushbuttons from the bottom, and slot the slide switches in from the top. For each leg do the following: Image #1: Assemble the following material. Settings. Select a wall thickness of at least 1/8”, but 1/4” will ensure that if a large impact is taken, the frame will stand up to it better. 1. Inside the anemometer there is a magnetic hall sensor on the base and a magnet on the. Then install the assembly one by one. Tie a knot between the two slots for the base joint. I also made the anemometer with the 3D printer, and below you can find the STL files. All what you need to built a drawing robot that works with the most of free softwares. ) Step 6: X Axis. Step 1: Get Elevation Data. This is where the scale and intricacy start to rise. Settings. Controlling the order of cuts. First of all, we learn how a generic CNC system works (by assembli… This will allow fine adjustment in 0. Step 4: Install Filament Feeders. Hexagon Shelf. The Raspb…Step 11: Print! Now print up the ornament! You can use a home printer like the MakerBot, but some of the details might get lost. Click on the CHOOSE A FILE button. Twitter: @mikel_llc Profile. All of these 3D models were generated algorithmically from Processing using the ModelBuilder library by Marius Watz. 3 More Images. Step 7: Diamond Shape Pendant & Triangular Shape Ear Rings Set. Already a subscriber? Continue with the provider and email address you used when you subscribed. Step 1: Navigate to the Printers Tab to Download the Latest Version of 3DPrinterOS Software. Sponge gourd seeds pasted using adhesive. To create this model you are going to need a lot of nails, time and patience. h)" Replace the default definition of #define MOTHERBOARD with your motherboard. Most of my plastic waste comes from failed prints and leftover strands of filament which I want to recycle into fresh filament using Filabot. ( NOTE: The dimensions in the image above are all in millimeters) This is going to be the base for the 3D printer. Step 3: Cutting the Metal. There are a few ways to tell that the motor you have is a BLDC, as opposed to a stepper or brushed-DC motor. Kits usually contain most of parts needed to assemble the printer and can be divided into two main types: Scratch Built 3D Printer – This 3d printer DIY kit is for those who prefer to build thing from scratch, or in other words go to DIY RepRap route. Bounce into some top-notch tips and tricks that'll get you 3D printing awesome springs in no time! Advertisement. 3d Printing Service. - An enclosure as air tight as possible to keep heat in and keep dust out. October 13, 2023 Report # AMR-3DP-ELECT-1023Step 1: The Main Class. Draw a tangent to tangent line between these 3mm circles (click and hold the first circle, drag over final circle. Continue with Microsoft. Price: Check latest price at Amazon here. Peel the protective film off of the back of the rear arcrylic sheet and attach the Power Supply and Print Controller. Do NOT add water yet. (THESE PARAMETERS ARE FOR PLA FILAMENT NOT ABS FILAMENT) Basic Tab: Layer Height: 0. . Tagged with: diy 3d printer • EV3 • hot glue gun printing • instructables • lego • lego 3D printer • legos. If you purchase using a shopping link, we may earn a commission. Magnets, copper wire, and ball-bearings are ordinary components. Free STL Files & 3D Printer Files: The Best Sites in 2023. If you have a smart phone it may be the best place to start. Printables Basics Buyer's Guides News Reviews. Here is the backpack accessory I created for my lego figures, primarily as an accessory to my zombie slaying figure. EWaste 60$ 3DPrinter. Instructables contributor Luke Rodley shared a 3D printing project that’s as much a course in 3D design as it is a 3D print job. It’s actually a mixture of home depot and 3d printing stuff. 40 3. Here are 4 solutions accessible to all:3d printed circuit printer boards3d view custom printed circuit board example Print out the circuit board! how 3d printing can cut costs on pcb3d flexible circuit copper print printer pcb printing board boards printed pcbs 3dprint circuits using etch filament etching utilizes instructables. Step 7: Attach Glue Gun Internals. Step 1: Problem 1: Side Mounted Filament Holder. 12. Insert the base joints of each finger into corresponding slots in the 3d printed palm. All 3D modeling programs start out with the basics of working in 3D dimensions: simple shapes and geometries. Now roll the brayer onto your block to transfer the ink. After the files print, the vine attaches to the pumpkin top with a drop or two of super glue (cyanoacrylate). Laser Lifter - Ortur Laser Master 2 (20W) - 3D Printed. Solder the first three pin male header to the 40 pin socket as follows: header pin 1 ---> 5V power. The following step is to start the server at port 80: AT+CIPSERVER=1,80. Then, further secure it by adding a bead of glue over. The Z axis is responsible for the fine positioning of the bed to create the layers of the 3D print. Fix the servo to the main base using the selftapping screws supplied with it. From here we open Makerware software and scale all files to 100%. Download files and build them with your 3D printer, laser cutter, or CNC. And tramming the axes and the spindle might be as well. To win an UP! 3D Printer, simply post a Step-By-Step, Photo, or Video Instructable that shows something utterly amazing that you have made. This 3D scanner is built using 3D printed parts, featuring both open source software and open source hardware files. The easiest thing to do is do a rectangle (and you can optionally curve the corners). Improved significantly with new concepts for printers. Printers have a ton of brushed DC motors of all sorts. 1) Download install the Arduino IDE and get the latest version of Marlin or your printer MFG available version that has auto-leveling in the Configuration. Exists some variant of this module, but all have a processor L106 32-bit RISC microprocessor core based on the Tensilica Xtensa Diamond Standard 106Micro running at 80 MHz, when. The 3D printed model of the F7 B unit locomotive has been created to accurately capture the distinctive features of the original locomotive. There is a lot of debate online right now about Prusa’s latest machine. Insert a piece of filament and cut to length. In the photo you can see four discs. Clamp the jig, mark the new leading scribe, drill the holes, move the jig, until you've placed all the holes you need. The shape and size of this 3D model is designed to challenge 3D printers. The da Vinci Nano is an inexpensive 3D printer that's simple to use. It uses a Raspberry Pi computer for the brains, a Raspberry Pi RP2040 based microcontroller to control the movement, and the Raspberry Pi Hi Quality camera as the telescope. Sep 2, 2023 - Explore Gary Stoppenbrink's board "3d printer" on Pinterest. h in Arduino. Additionally, having an. Exposure Time is the amount of time that the light source will expose each layer during. This is a list of the things that are mostly necessary for the hardware setup: Gantry - Alas, an important aspect to building a 3d printer is acquiring a gantry! We used a modified shapoko CNC machine in order to gain control. 3DPOD Episode 176: 3D Printing in Singapore with Chaw Sing Ho, CEO of NAMIC. . LEGO 3d Printer: This LEGO printer is based on the Prusa I3 rework printer. Technology: FDM, SLS, PBB, or STG. Install the Driver Gears- Mercury To Mars on the left side (driver side) by inserting the 1/4" shaft at the base of the gear stack into the 1/4" hole in the center of the driver side frame as shown in illustration. If your 3D printer is of the resin variety, don’t worry, you can make. It has a 3. 3D printers are everywhere and can make just about anything! You'll find inspiring beginner, intermediate, and advanced projects and classes in this collection. The laser is very good for making jigsaws because the cut width, or kerf, is only 0. Unscrew the z-axis from the base of the 3D printer. You'll also learn the ins-and-outs of desktop 3D-printing. Here is our pick of the best 3D printers. 12" x 3/4" threaded galvanized steel pipe. Now apply glue to the faces of the 3D printed feedthrough parts. Instructables. Step 4: Print and Assemble the Motor Mount. Use a pressing tool to compact the pulp. Build a DIGITAL MAGIC MIRROR by DIY Machines in 3D Printing. You can get your elevation data from anywhere, but one source I've had a lot of success with is opentopography. Step 2: The Coil Ring. Draw a front view sketch with tool icon. I didn't use any templates and it turned out fine, but to be extra sure,. May 15, 2020 - Explore jose castro's board "Circuitos" on Pinterest. Instructables member Icare has completely redesigned just about everything, which I thought. 1) Drag your image into the browser. Check out how to make your own lithophane 3D print!Check out the best collection of the best websites to download 3D printing files. 3D printer enclosures protect your printer, improve printing quality, and reduce noise and odors. Since I first built my 3D printer, I've seen the possibilities for modifying and adding to it in order to increase its capabilities. 2. 4 that connects them. Some 3D printed parts. After I was done mourning over my 20$, I decided to make my own. Learned a lot. Place the ON/OFF switch in the 3D printed base, and insert the PCB slowly. Introduction to building your own 3D printed quadcopter drone. Requires the following: OctoPrint Server and the User API Key from your user account… EWaste 60$ 3DPrinter: This project describes the design of a very low budget 3D Printer that is mainly built out of recycled electronic components. Next attach the wires from the motors to the ESCs. Build the frames of the cabinets in the usual Ikea way. 3d printed circuit boards & pcb 3d printers explainedPrinting circuit boards with the atmel-powered ex¹ 3d circuit printer board nano voltera desktop printing dimension kickstarter presages hit layer multi future extruder smash boards computerworldSolderless instructables. A 3D printer deposits little drops/line of molten plastic from a headed tip (nozzle). If you just want to 3d-print the stl file use the free Autodesk Print Studio program to process the file for your specific 3d printer. Instructables. While the actual 3d printer can be built for less than $60 you will still need resin to print anything. If your at all interested in DIY CNC (do it yourself computer numerical control), then Instructables is the place to be. Remove the block and smooth the joint. com. Z lift height is the distance between 3D model and bulid plate. Read on to learn all about the best ABL sensors!By 3D printing a Shoji lamp, it definitely goes against traditional construction methods. In the photo you can see four discs. Then attach glue gun head to the previously put-together extruder parts. 3D Printed Electronics 2023: Market Study & Forecast. BCN3D Technologies continues to take important steps in order to achieve our goal of bringing digital. The Instructables Workshop has featured lots of amazing 3D printing. I broke 7 part of it and after that I decided to give up at this point with this frame and buy one. To be able to print your model on your 3d printer, you need to make sure you have a watertight model (no holes in it). If you need an intro, check out this instructable. Click on the CHOOSE A FILE button. Rails are short enough to fit in any regular 3d printer. Step 2: 3D Printing the Parts. If you choose. It can be your small family business. Intro:€ Homemade 3D Printer Filament Extruder This is a basic tutorial for building your very. Place the desktop on top of the frame, and adjust its position to get a 1 inch overhang on all sides. The ones that were produced on the Objet printer that Instructables use have turned out great. Step 4: Z-Axis Installation and Tramming. by Reef Morse. RAMPS 1. Test fit the filament and lightly sand both sides of the box wall for better glue adhesion. However, the designing process is undoubtedly a huge threshold for most fans. There’s a couple of simple tips: - Make sure you get some kind of filament extruder. 3D Printers. 2mm but it's not a bad idea to experiment with yours to find where it is. Instructables 3D Printed Robot Arm. Industry MAGNUM. Ability to cut 6, 5, 4, 3 and 2-faced "boxes". Using the Image To. The important thing is that the print is set to “solid infill”. 4. 08mm. 3D Printed Electronics 2023: Market Study & Forecast. Make sure to press the adapter on while still hot. Many forums have discussion on how to stop the false triggers and most of it doesn't seem to work 100%. Report comment. It uses a Raspberry. We've got detailed step by step instructions on how you can build your own CNC lasers, CNC mills, CNC foam cutters, self-replicating CNC's and even a CNC chocolate 3D printer!Continue with the provider and email address you used when you subscribed. Any good keychain has to start with something you care about, a great logo! 1) Google "sxsw logo" use the image search, 2) Select a logo, keep a few things in mind: - Bigger is better, try to avoid very small images or your keychain may come out grainy. For more inspiration, read Best 17 3D Pens, 30 Printing Ideas & Templates . They will be mounted on top of the intermediate Billy board. by Lauren Fuentes. Balloon Powered Car. (If you can't see the interactive 3D model above, its probably because you're not using a WebGL-enabled browser, or you're using the Instructables Mobile app) Here you can download the complete CAD-file. Click the "insert" icon on the task bar, follow the drop down menu and select "insert mesh". Printables; Basics; Buyer's Guides; News; Reviews; Get It 3D Printed. Solder the 40-pin socket to the center of the board. A2000mW A5. I've also included the files "Bolt. step for other CAD-programms : SLS 3D-Printer v54. Take lots of measurements of the night light, it helps to write them down on paper. Build a Personal Locking Container. 2: Put a ring of hot glue around the rim of the fan to seal it. Using rapid prototyping tools like 3D printers and CNC routers, making a lens is easier than you might think. I don't have any LEGO Mindstorms products. Now, try to slide it out from under the nozzle. Instructables. dragonator's Instructables. by AMMONITEa in 3D. Scroll middle mouse button to zoom in or zoom out. Today our world seems as though it's moving faster than ever. 3D Printing. I made a demo piece using Fusion 360, Within, and Netfabb. Three fins sets of type A are needed (one shown) and one of type B launch lug. 3D Printing. Disable the labels and use #000000 (black) as line color. If you're looking for cool 3D models, you're not limited to Thingiverse. Owned by Autodesk, Instructables is a free STL file and general project building site that encourages designers to post step-by-step instructions on how to. Spray canned solvent aerosol onto part. CNC Student Design Challenge. But on a printer this size tramming may become an issue. The Ultimate Human Sized 3D Scanner With Raspberry Pi.