If you wish, you can contact me directly through this page with any questions or comments. This would be the appropriate place if you would like to add constructive content and comments to this website.
Before you write, consider using this website's FORUM. Your questions or comments can benefit like minded people trying to accomplish similar tasks. If you have already established a conversation from the method on this page, email me approval to bring it to the FORUM. Please let me know if you would like to see a unique section added to the forum.
The new FAQ (Frequently Asked Questions) and INFAQ (Important but Not so Frequently Asked Questions), in no specific order:
Q: What are the acceptable materials that I can cut?
A: The machines on this site can cut a wide variety of materials. If there is an end mill (cutting bit) that is available on the market, the machine can cut it. The thickness is only limited by the end mill length. This is possible with these CNC machines and other machines on the market because the machines can be controlled in such a way that the material can be cut using depth per pass, feed rate, and spindle RPM.
Q: What is Backlash?
A: Without getting into much detail, backlash is the amount a machine's mechanism can shift due to looseness in the mechanism. All machines have backlash. Backlash can exist various places in a machine: linear motion bearings and bushings, couplings from one shaft to another, loose set screws, loose clamp collars. clamp collars that are not positioned correctly, and temperature changes that affect linear expansion and contraction.
Q: What is better: Roller Chain/timing Belt or Lead Screw?
A: Lead screw is the rotational translation to linear motion driven by a screw using a stepping motor to turn the screw. Lead screw has the potential to have high resolution but can exhibit backlash in many places in the mechanism, especially through temperature change. Roller chain is the translation of motor rotation to linear motion by means of turning a sprocket or drive pully on ta roller chain or timing belt. The roller chain or timing belt is always in tension, so backlash through this specific mechanism is minimal to none. Since there is extremely little to no backlash, microstepping will enhance the resolution and meet or exceed the effective resolution of the lead screw. Roller chain or timing belt also allows the motor to use low RPM which increases the torque at any given speed as compared to the lead screw.
Q: How do I configure my control program (i.e. Mach3, EMC2, etc.) for roller chain or timing belt steps per inch?
A: First, you will need to know the pitch of the roller chain, or timing belt. For example, #25 roller chain is .25" (1/4") pitch and #40 roller chain is .5" (1/2") pitch. Timing belts are similar and you will need to search the specifications of your particular drive pulley pitch. Take this pitch and multiple this with the number of teeth on the drive pulley/sprocket. This will give you the number of inches around the pulley/sprocket. Now, take the number of steps per revolution that the motor will output. This will be the number of full steps that you motor produces (typically 200, or 1.8 degrees per step) multiplied by the microstepping per step to which the driver is configured. Divide this number by the inches that was calculated from the drive pulley/sprocket. Here is an example: If the motor produces 200 steps per revolution and I am driving it at 1/16 microstepping and my sprocket pitch is .25" with 9 teeth, my formula would be:
(200 steps * 16 microsteps) / (.25 inches * 9 teeth) = 3200 steps per revulution / 2.25 inches = 1422.222 steps per inch
Q: How do I configure my control program (i.e. Mach3, EMC2, etc.) for lead screw steps per inch?
A: You will first need to derive the number of turns per inch that your lead screw produces. If there is only a single start (typical all thread screws), then the turns per inch is the same as TPI (threads per inch). If there is multiple starts, then the number of starts is divided by the TPI to determine the turns per inch. For example, 10 TPI with 5 starts is 10 / 5 = 2 turns per inch. Now that we know this, we can get the number of steps per inch as described in the previous question: take the number of steps per revolution that the motor will output. This will be the number of full steps that you motor produces (typically 200, or 1.8 degrees per step) multiplied by the microstepping per step to which the driver is configured. Simply multiple the number of turns per inch and the number of steps per revolution and you will get the steps per inch. Ok lets see the formula:
200 steps * 16 microsteps * 2 turns per inch = 6400 steps per inch
Q: I have a 4 wire motor, but your videos instruct me for 8 wires. How do I know which wire goes where?
A: Connect the black wire to the A+ on the driver, green to the A-, red to the B+ and blue to the B-.