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Troubleshooting Your New CNC Installation
Below are a few problems and solutions that have been noted for issues on some new CNC installations. Before calling Sherline, please look over this list to see if an answer to your problem has already been posted. If you do call, please have your version number and/or approximate date of purchase ready. For a more complete troubleshooting guide for additional CNC issues that go back to earlier versions see http://www.sherline.com/trouble.htm.
CAUTION: When opening up your computer or driver box, please take appropriate grounding precautions to assure that static electricity does not damage delicate components on your circuit boards.
• Finding which version of Linux you are running:
In order to apply the appropriate remedy, it is usually necessary to know which version of Linux your machine is operating under. Here is how you find out:
Ubuntu version (EMC2): In the top menu bar of the desktop click on “System.” In the dropdown menu, click on “About Ubuntu.” In this box it will list the current version number.
Debian version (EMC): When booting up the computer, after the biostar logo appears on the screen a version page will show briefly. Hit the up or down cursor arrow on the keyboard to freeze the screen so you can copy down the version number.
Also, look at the backup CD’s that came with your computer or driver box. The Instructions/Utilities disk and Installation disk should have the Sherline version number noted on them.
• The computer runs a program and the stepper motor power is on, but none of the motors move.
This is the most common call we get. Most likely you have not yet connected the 25-pin parallel cable to the computer. (This is the large cable with a wide, flat connector at each end.) This cable, which sometimes used to be referred to as a “printer cable” comes from the driver box in the bottom of the computer case (or from the separate 8760 driver box), and the other end must be connected to the computer’s parallel port. This is how the computer communicates with the driver board and stepper motors.
• The stepper motors all stopped running at the same time and now won’t move.
Resettable fuse (2009): Starting with driver boards made in 2009, an additional level of protection was built into the board as a running change to automatically shut off power to the motors if an electrical anomaly that could damage the board is detected. Take a look at your setup to determine that nothing is physically jammed and then turn off power to the board using the power switch on the side of your computer or back of your driver box. Wait a few seconds and turn it back on. If the motors now work, it was the protection circuit doing its job. If this happens several times, you might want to take a look at your surge protector, other sources of electrical interference or physical obstructions that might be causing the protection circuit to activate. Before restarting, it is advisable to check that all cable plugs are fully engaged and dry (no liquid coolant contamination), and check each axis for free movement (lubrication and gib settings) to be sure those weren’t a source for the problem. If rebooting the driver power supply does not fix the problem, you may have a burned board and will need to call for technical assistance, but always try resetting the power supply before calling Sherline.
Replaceable Fuses (2011): In mid-October, 2011 replaceable fuses were added to the driver circuit board for additional protection. A blown fuse on one or more axes can be due to any of several different reasons; such as, motors plugged in or unplugged while the power is on (“hot plugging”), stalling or over-driving a motor by taking too heavy a cut, etc.
First try restarting the driver box as noted above. If this does not solve the problem, to change the fuse or fuses on a computer-mounted driver board, first turn off the computer and driver board power supply and unplug the power cord. Remove the side panel of the computer (the one with the machine on/off switch). Inside the PC you will see the circuit board attached to the top of its own power supply on the bottom of the computer case. There are four small vertical green fuses inline behind the DINN cable receptacles for each axis. You will find two replacement fuses taped inside the aluminum housing below the CD/DVD drive. Remove the fuse(s) from the non-functioning axis (axes) and replace the existing fuse(s) with a new one. Once the fuses are replaced, re-install the cover and turn power back on. If you are using an external 8760 controller you will find the fuses taped to the inside of the lid. Follow the same replacement procedure described above.
• The stepper motors make noise, but nothing is moving.
The likely problem here is your mill is binding or not properly lubricated. With the more significant stress of quick back and forth motions and the high number of turns possible in a short period of time your mill will need to be more frequently lubricated than hand driven applications. Under continuous cnc use we recommend that Sherline cnc lathes and mills be lubricated once every four hours. Refer to the mill manual or http://www.sherline.com/lubricat.htm for more detailed lubrication instructions. Note also that when stepper motors are powered up but not yet running they do tend to make a slight buzzing or hissing noise. This is normal.
• The computer is plugged in and all cables are connected properly but the computer will not boot up.
Unplug the computer and plug a test plug or a different electrical device into the same outlet to confirm that you do have power. (On some wall outlets the lower outlet is controlled by a wall switch that may be in the off position or a home circuit breaker may have blown.) If it still will not power up, the power supply may be damaged. Call Sherline to obtain an RMA number to replace your PC power supply. If not under warranty you may do the repair yourself by purchasing a standard PC power supply (≥400W) and soldering 3 wires to the AC inlet for PCBA power supply.
• One or more stepper motors skip steps during rapid travel at full speed.
A fact when dealing with stepper motors is that the faster they turn, the less torque they have. This is because the power for each pulse is on for shorter periods of time; therefore, it's a good idea to keep feed rates 20% below maximum when running programs with many short moves, particularly on the Z-axis. The maximum feed rate in EMC2 is 22 in/min. Therefore it is good practice to keep your feed rate below about 18 in/min or 450 mm/min. Some of our customers have counter-balanced the weight of the Z-axis with a simple rope-pulley-weight device to reduce wear on the Z-axis leadscrew. See the http://sherline.com/CNCproj.htm section of our website for a photo and description of how one person did this. You'll find that the stepper motor system we use quite reliable and capable of running complex programs without losing steps when used properly.
G-code tips: Start and end each program with a percentage sign. Put a g40, g49, g21 (Metric) or g20 (inch) and g90 in the first line of code to cancel out any previous codes that might be left over from the last program, and always end the program by returning to the same place you started. Keep in mind which g-codes EMC2 does and does not support. Some canned cycles are not supported, for example.
• One or more of my stepper motors is running in the wrong direction. (Modifying .ini files)
NOTE: The ini files determine the basic functions of the EMC. Changing them improperly can have unwanted effect on the operation of the program. Be sure to follow directions below for your particular version of Linux carefully while making changes. It would even be a good idea to save a copy of the original ini file on your desktop or to a flash drive before making changes so that you could always go back to the original configuration if problems occur after changes are made.
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A tip regarding axis direction Remember that on a mill the tool is fixed and the table moves. When using the jog controls, at first it may seem like the X and Y axes are moving in the wrong direction, but when you picture the move in relation to the cutting tool it makes sense. Programming directions relate to APPARENT TOOL MOVEMENT, not table movement. Therefore, a positive move on the X-axis will result in the table moving to the LEFT, making the tool appear to move to the RIGHT. A positive move on the Y-axis will result in the table moving TOWARD you making the tool appear to move AWAY from you. The Z-axis is more intuitive with a positive move resulting in the tool moving UPWARD. (A positive move on the A-axis will cause the rotary table to rotate CLOCKWISE.) This is the way full-size CNC machines work too. |
Changing axis direction, UBUNTU Linux (Lucid v6.0, after mid-2011):
If an axis really is moving in the wrong direction (see note above) you can change the direction of travel in the ini file for your inch or metric mill or lathe. To find this file go to the “Places” menu tab at the top of the screen and click on it. Open the following folders by double clicking on them: Home Folder>emc2>configs. In the Configs folder choose either Sherline4Axis for the mill or SherlineLathe for the lathe and double click on the appropriate folder. This will show you the ini files.
If, for example, you open the Sherline4Axis folder, you can choose files called either Sherline4Axis_inch.ini or Sherline4Axis_mm.ini depending on which mill you have—inch or metric. Double click on the appropriate filename to open the file.
In the window that opens, click on “Display Contents” to open the ini file. Scroll down to the section for the axis you wish to change. Each axis is labeled by number rather than letter. Axis 0 is the X-axis, Axis 1 is the Y-axis, Axis 2 is the Z-axis and Axis 3 is the A-axis (rotary table). Look under the appropriate axis for a heading for SCALE. There will be a number 16000 after it. It will either have a minus sign in front of it or not. To change the direction of travel, either delete the minus sign if it has one or add one if it doesn’t. When done, select “File>Save” to save the change and close the box by clicking on the “X” in the upper right-hand corner.
Changing axis direction, UBUNTU Linux (v5.0):
If an axis really is moving in the wrong direction (see note above) this means that a value in your ini file for that axis needs to be changed. To do so you will need to open the file called mill_inch_mini.ini for mills with inch leadscrews or mill_mm_mini.ini for mills with metric leadscrews. (lathe_inch_mini.ini and lathe_mm_mini.ini for lathe programs.) The files are located at Places>Home Folder>emc2>configs>Sherline for the mill and Places>Home Folder>emc2>configs>Sherline-Lathe for the lathe. When you open the Sherline or Sherline-Lathe folder, you can then double click on the appropriate ini file to display its contents. Scroll down to the section for the axis you wish to change. Each axis is labeled by number rather than letter. Axis 0 is the X-axis, Axis 1 is the Y-axis, Axis 2 is the Z-axis and Axis 3 is the A-axis (rotary table). Look under the appropriate axis for SCALE. There will be a number 16000 after it. It will either have a minus sign in front of it or not. To change the direction of travel, either delete the minus sign if it has one or add one if it doesn’t. When done, select “File>Save” and then close the box by clicking on the “X” in the upper right-hand corner.
Changing axis direction, DEBIAN Linux Version (up to v4.28):
If an axis really is moving in the wrong direction (see note above) this means that a value in your ini file for that axis needs to be changed. To do so you will need to open the file called mill_inch_freq.ini for mills with inch leadscrews or mill_mm_freq.ini for mills with metric leadscrews. To find the ini file for your version, click on the "K" menu icon in the lower left of the screen and then click on the "Personal Files" icon to open the Home folder. (You can also click on the "Home" icon in the menu bar at the bottom of your screen.) In this folder you will find the ini files mentioned above. Click on the appropriate one for your machine (inch or metric) to open it. Scroll down to the section called "First Axis" and find the line labeled "INPUT SCALE". The value will be 16000. To change the direction of movement of that axis, add a minus sign in front of the number so it reads -16000. (If it already has a minus sign, deleting the minus sign will change it to the opposite direction.) The axes are not labeled by letter, but axis 1 = X, 2 = Y, 3 = Z and 4 = A.
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