Fadal Manuals

Below is an accumulation of information concerning common topics regarding technical aspects of the machine and the products we currently offer. The list is constantly growing, so check back often and give us a call if you need more help.

Legal Disclaimer:
No advice -  This website contains general information about service matters.  The information is not advice, and should not be treated as such.

Spindle Drive System - The spindle drive system has multiple failure points that need to be considered; it's not always the Drive or the Spindle Motor.
  Spindle Drive Functional Diagram: A page link for more information about the Spindle Drive System and possible failures.

Motor Encoders - Simple ways to test the spindle and axis motor encoder...

  

Spindle Failures - Bearing failure is the most common reason for a spindle to fail.  Today it seems the "end all" solution is to sell you an "upgrade" to Ceramic Bearings.  Ceramic bearings are not new, they've been around for over 30 years. While ceramic bearing are in some cases "better", as the saying goes "Better is the enemy of Good".  First off, not all ceramic bearings are the same, secondly if ceramic bearings were so good, they'd be the standard of the industry.  There are many different ceramic bearings; the best are solid ceramic while the cheapest are steel bearings coated with ceramic.
The basic advantage of a ceramic bearing is roundness, stiffness and weight, which depending on the application can make the difference between success and failure, especially above 20,000 rpm.
Stiffness can cause chatter which is a factor of bearing stiffness, span, preload and shaft design.  It's all a balance of design, the ultimate design is to have more bearing preload at the lower rpm and less preload and the higher rpm range.  In the early development of the Fadal spindle we actually had experimented with a dynamic preload spindle.  It automatically changed the preload according to the rpm.  Unfortunately it was too complicated for production.
The correct preload is a balance between spindle rpm ranges- higher rpms require less preload between the bearings.  Less preload reduces the heat but increase spindle "chatter" during low rpm cutting.

The biggest cause of spindle failure is Contamination and/or Heat.  Below is a list of common reasons why spindles fail.
Contamination: Typically, coolant gets by the labyrinth seal at the spindle noise and brakes down the spindle grease.  It's easily detected as the grease turns a milky white color.
Heat is another spindle killer.  Duty cycle and preload contribute to spindle heat failure.  A simple way to tell when a spindle is running hot is by checking half way up the spindle taper.  At this point the inner race of the bearings is at the thinnest point of the spindle shaft wall thickness.  The rule is "if you can't keep your finger on it at this point; it's too hot".

A simple warm-up procedure; 5000 rpm for 20 minutes in the morning is very important for all grease pack spindles.  It helps to distribute the grease evenly, after sitting over night.
Belt Tension - The HI/LOW idlers need to be cycled.  Shifting ranges relieves the belt tension caused by the hydraulic idlers.  The torque of the belt causes the idler to keep going inward which increases the belt tension between the spindle motor and the spindle pulley.  This causes an excessive load on the top spindle bearings which increases the heat factor. This heat factor can cause the grease to migrate down away from the top bearings.  Also, cycling the idlers will increase the belt life by reducing tension on the belts.
Another important check is to verify the idler air supply is less that 70 psi.  The machine has two regulators; one for the tool in/out and one for everything else.  Too much pressure to the idlers will cause excessive belt tension and damage the top bearings.
Spindle Coolant - verify that the coolant flow hasn't been reversed.  The coolant must flow into the bottom of the spindle and out the top of the casting (return line).  It's easy to get the lines backwards.
Verify the chiller system is full and cycling correctly.  The temperature differential of the chiller input verses its output is about 1.5 degrees.  The BTU capacity of the chiller must not be exceeded by the run time of the spindle; the chiller system needs spindle off time to reduce the heat inside the spindle.  For excessive duty cycle, considers adding another chiller.

Tool Crash - Crashing the tool into the part can cause bearing ball/race damage and/or actually bend the spindle shaft enough to cause bearing failure.

CNC Memory Errors - The CNC memory uses a "checksum" method to verify the integrity.  If the memory becomes corrupted (fails a checksum test), the "memory error" message is displayed.  One of the most common reasons for this is the battery on the 1400 CPU board is failing.  The battery backup design uses a combination of a capacitor and a battery to maintain the memory after the power is off.  The capacitor does most of the work; it last approximately 3 days.  The battery power switches in after that point.  Even thought the battery might measure 5 VDC, it's only under a load that the battery can be properly tested to see what voltage it can hold when under the load from the memory chips.  Dropping below 3.5 volts for 100 nanoseconds will cause a memory corruption.
Many CNC problems can happen if the memory does become corrupted.  It depends on the area of memory that has been corrupted.  Sometimes the keyboard will even quit responding.
In most cases the battery needs replacing and it is best to send it in to us for in-circuit testing and battery replacement.
You can usually recover temporally by zeroing the CNC memory using the control diagnostics.  Be sure to save your program, offset and record the machine parameters (SETP) before zeroing all the memory because you'll need to restore them after zeroing all of the control memory.  Leave the control power on and push in the E-stop button instead of powering off the machine.  This will prove the battery or the switching circuitry is faulty.

Resolver Faults - A resolver fault occurs when the axis controller card doesn't detect the returning sign wave signal from the resolver.  The resolver signal originates from the clock board and is shared by all the axis motors.  If one resolver shorts the sign wave; all the resolvers will fail. 
We added the 1060-0-1 board (it plugs into the motherboard) to separate the signal for each individual motor and help identify which axis is failing.  This board could be bad a not allow the resolver signal to reach the motor.  Early model machines did not have this board.

Another potential failure is with the resolver connector at the motor.  The six pin Molex has been know to fail and give a marginal connection.  You can put pressure on it in various direction while having someone try and reset the fault.
The resolver bearings can fail and cause problems with the signal.  Bearing failure is often due to the misalignment of the motor end shaft and the resolver shaft.  The Helical coupler does not allow for parallel shaft misalignment over .005" and simply replacing the resolver will eventually fail again.  You need to replace the resolver coupler with a better designed coupler.  Contact us for more information.

Testing a Resolver - You can test a resolver to see if it is indeed bad by using a voltmeter and measuring the resistance of the coils inside the resolver.  The Resolver is constructed of three coils; two excitation coils and one reference coil that is connected to the axis controller card.

 
The image shows the interface connector and the associated coil connections.
1) Check Resistance:
   Pair A = 70 to 80 Ohms
   Pair B = 190 to 220 Ohms
   Pair C = 190 to 220 Ohms
B and C will have the same values; the actual value depends on the manufacture.
2) Check for Coil-To-Coil shorts:
Any other pin combination besides the three individual pairs must result as an open circuit.
3) Check for Short to ground:
Check resistance of each pin to Resolver frame (case).  They must not be shorted to the resolver frame.
4) Check the voltage when connected:
   Pair A = 1.7 VDC
   Pair B and C = 3.5 VDC
Pair A goes directly to the 1010 axis card; J2 bottom bullet connector

RS-232 Using A USB Port Adapter - Many customers using software to upload or download with the Fadal machine have been experiencing problems after upgrading to a new PC.  The problem is most new computers do not have physical RS-232 serial ports.  The solution is to use a USB to Serial adapter.  The problem is some of the adapters do not work with existing software; such as NCFadal or MasterCam.  Not all adapters are the same; many of them are made from inferior components and/or the device drivers are poorly written and are not very compatible with the latest Windows operating systems (IRQ type conflicts).

The simple solution is to use a industrial grade adaptor.  We've had customers solve their problems using a $36.50 product from usconverter.com
Click Here for more information.

More Information Coming Soon... check back often.