NEMA Motor. A NEMA 17 stepper motor. The US-based National Electrical Manufacturers Association creates standards that are developed by the manufacturers through a voluntary consensus to provide descriptions of how things should be. NEMA ICS 16-2001 (Motion/Position Control Motors, Controls, and Feedback Devices) describes stepper motors and is the NEMA standard usually referred to when talking about the NEMA standard in the context of RepRap, stepper motors and 3D printers. In section 126.96.36.199 of that standard, NEMA chose to label stepper motors (e.g. "NEMA 17") with the size of their faceplate in tenth of inches. So a "NEMA 17" has a 1.7 inch by 1.7 inch faceplate. By standardizing the stepper motors (the faceplates, flanges and screw holes), you know ahead of time that one NEMA 17 motor will fit into the mounts of another NEMA 17 without having to redesign anything.
This makes swapping components easier. Full NEMA name The full NEMA name of a stepper motor is written as: Some examples: Some (all?) Pololu stepper driver board. Pololu stepper driver board Release status: working Please note: Pololu stepper driver boards has 0.05 ohm sense resistors instead of StepStick 0.2 ohm. A Pololu stepper driver board is a well known RepRap machine stepper motor driver. The Pololu stepper driver boards are made as pluggable modules to a electronics motherboard. A good reason of this design is, that it is easy to exchange the Pololu boards when troubleshooting - or when a board has burned out. List of Boards Pololu driver boards (8+8 pins): Pololu driver boards with Voltage Regulators (longer boards - 8+14 pins): As user Nophead has pointed out, that Pololu driver is a nice design, but with one big shortcoming: it will run hot, and is difficult to cool because it's so small. Alternatives Tuning motor current A4988 and similar Per the A4988 datasheet, the calculation for the maximum trip current is: I_TripMax= Vref/(8*Rs) As another example, aiming for 50% temperature rise on 1A rated steppers by using max 0.7A, so rearrange it as: or.
Pin Bed. Last Updated: 12th February 2012 My laser cutter came with a honeycombed panel which can be used to support sheet materials for cutting. However, the mesh area is only 170x190mm and the nature of the honeycomb means that the beam frequently hits the edges of the mesh (which can lead to scorch marks on the underside of the material being cut). The honeycomb cells also tended to trap vapours and small bits of material that fall out of the work piece. Removing the top and bottom edges of the frame improved things as a) it allowed longer sheets to be placed on it and b) the slight gap this created under the top edge allowed (prior to my replacing the installed fan with head mounted fume extraction), vapours to be sucked out from below. I have now replaced this with a pin bed: I'd had my laser cutter for some time prior to making this modification and had only ever wanted to cut sheet materials betweem 0.25mm (thin card) and 3mm (acrylic) thick. ...and that's the pin bed complete.
Weistekengineering. Adventures in DIY Engineering: 40 Watt Chinese CO2 Laser Upgrade with RAMPS & Arudino. 3/31/2015 - Updates made in the Firmware and Inkscape plugin section below. Thanks go to Turnkey Tyranny for the many improvements and fixes he's contributed. Also, I would like to note, there are many variations on the Laser supplies. Please be very aware whether yours is an ACTIVE LOW or ACTIVE HIGH enable signal. The firmware below is ACTIVE LOW. Introduction: I've wanted to start playing with Laser Cutter/Engravers for quite a while. I finally happened across a great deal on a Chinese made 40 watt Laser Engraver with the Moshidraw software and control hardware. Please excuse the picture quality, when I get some time I'll try to take better ones. Whats Needed: - CO2 Laser Cutter/engraver ( Electronics ($65) for everything on ebay - im sure theres other deals out there too! - Modified firmware the Lansing Makers Group started. Additional Information/References: Lid Interlock:
Build Thread Cheap 40W Ebay engraver/cutter (K40) upgrade thread - Page 4. Home made laser power meter. Identifying Unknown Plastics. This is a piece of free-burning ABS tubing showing characteristic flame color and smoke. The burn test, as it’s known, correlates a plastic sample’s composition with a set of observable properties including… whether or not the material will freely burn in air when a gas ignition flame is removed,the color of the flame, the smell, the presence or absence of molten drips, andthe color and properties of any smoke, esp. the reactivity of smoke with wet litmus paper.
Though useful, the burn test should be used with caution of the toxicity of many plastic combustion products, and need not be a first resort when confronted with a sample of unknown polymer. To risk stating the obvious, the first step in identifying a piece of plastic should be to look for a label. Since 1988, the SPI resin identification coding system (Wikipedia) has been widely adopted by plastics manufacturers to label their products for post-consumer recycling. Laser Cutter Materials - ATXHackerspace. There are a wide range of materials that the Blue Laser Cutter can cut, etch or mark - but some simply don't work (eg metals) and some are extremely hazardous to either humans or the machine itself (eg PVC and ABS).
It is therefore imperative that you check these lists before attempting to cut materials that you have not worked with before. It is not always obvious which materials will work - for example: Polycarbonate/Lexan produces flames and lethal chlorine gas which will rapidly corrode this $40,000 machine into uselessness and which is extremely hazardous to the health of people nearby. Yet Acrylic - which looks, smells, feels and tastes just like Lexan - cuts smoothly and cleanly and is one of the best materials to use with the laser! So check and double-check what you're cutting. Where to Find Materials There is a fairly good supply of materials at the hackerspace, which you can pay for in the store. Where to find materials to feed the laser. Safe Materials Cutting Etching Marking. 6.4mm (1/4) 3000 Alloy Aluminium Honeycomb to Buy Online - Easy Composites.
Product Description High performance aluminium (or aluminum) honeycomb exactly as supplied to the world's top composites engineering, aerospace and motorsport manufacturers. Used correctly, aluminium honeycomb can be used to reduce the weight and increase the stiffness of composite panels in a wide range of applications: This medium 6.4mm / 1/4" cell size honeycomb is an excellent 'all rounder' honeycomb suitable for a wide range of applications including motorsport, marine, renewable energy and transport. The 6.4mm / 1/4" cell size is a good balance between strength, weight and cost making this our most popular aluminium honeycomb.
Expanded Sheet Sizes We supply our Aluminium Honeycomb in unexpanded (block) form. This makes them much smaller (and more cost effective) to ship but most importantly ensures that they are delivered undamaged, ready to be easily expanded into a faultless sheet of honeycomb. Transport and Delivery Information Cell Size and Specification Thickness Technical Questions. CO2 laser cutter. 03/05/13: See here for a measurement of the output power using a thermal technique 19/11/13: I discovered I can do laser wire stripping!
Introduction I had been considering buying a laser cutter/engraver for several months, mainly attracted by the possibility of engraving designs into wooden boxes, ceramic tiles, glass etc. Any of the "Western" models were far too expensive (e.g. £17,000 for a Trotec engraver) so I therefore settled on a Chinese model, which are readily available on EBay. I initially contacted HPC Laser (www.hpclaser.co.uk) who are a UK distributor of Chinese machines. I was messed around for weeks by them - they didn't reply to emails, they said they had a machine but didn't, and so on. The machine is an SG40A Desktop Laser Engraver, made by Signstech International (aka "Strong Signs Digitech").
I have put more specific details and specs of the machine, including hi-resolution photos of the insides of the machine, on this page. Safety Setup Dirty optics (25/05/09). Laser Cutter. Gallery For a while I'd been noticing how cheap lasercutters had become on Ebay. I'd considered putting one on my list of 'things to look at when I next fancied a new toy', but was initially discouraged by some mixed opinions I'd read. My only immediate application would be for making SMD paste stencils, but I'm sure I could find other uses... Eventually I succumbed to temptation. Amongst the various Ebay sellers selling them, it was obvious by looking at other items they were selling that many (especially the Hong Kong ones) were just box-shifters, also selling all sorts of random stuff. I ended up going for a Chinese supplier with good feedback, who only sold cutters, laser tubes and other related items.
Model is Shenhui DC-K40, but the same unit seems to appear under different names. As expected, documentation (including video on CD supplied) was as appalling as we've come to expect from Chinese suppliers. Safety & quality issues How well it will last, only time will tell... Buying a Laser Cutter from China (Part One)… 2012 UPDATE: Check out the new laser cutter I built from scratch here -> New 24×18″ CO2 Laser Since building the CNC router last year I’ve become increasingly interested in adding a laser cutting/engraving head.
Scanning eBay I found lots of component parts, but I did not have the expertise to create a working system. In situations like this I’ve found the best thing to do is buy an inexpensive “complete” system and use this to discover how things work – eventually the goal being to use the technology in something bigger and better. I had noticed the 40W cutting units available for under a grand, particularly the ones sold under the “Strong” name – 40W Craftworks CO2 Laser Engraver&Cutter by strong_signstech. Although not a huge amount of information available online – I was able to find two websites (both UK-based) that had some information on the units: Andy Slater – bought one and converted it to run with Mach3 (something I may well be doing in time) The larger contained the unit itself.
Sam's Laser FAQ - Carbon Dioxide Lasers.