Selection of feed rate calculation method
The NC Feed rate dialogue allows the user to set the winding speeds and method to use to calculate machine feed-rates.
The Feed-rate dialog now shows the maximum speeds (feed-rates) for each axis and also the maximum accelerations for each axis. If an axis exceeds the maximum set speed in a particular line of motion the overall feed-rate will be reduced.
The accelerations are only used if the ‘accerations check box’ is ticked. If the velocity for the next motion cannot be reached within the time length of that line then the time for that line will be increased (ie the machine is slowed) such that the maximum acceleartion for the axis with the problem is respected. The acceleration functions are in an experamental state at version 7.27 and the effectiveness is dependant upon the setup and configuration of the winding machines motion (NC) controller.
The default velocity and accelaration limits are set in the machine configuration file (.sm file) described in another section.
The calculation mode options are as follows:
0Only specify a feed rates at the start of the NC main and NC sub -programs. The feed value used in the main program is the 'start feed' from the .SM file. The feed-rate in the sub-program is specified by the user but the default is the start feed.
1. Calculate feed rates for each NC block such the mandrels rotational speed remains constant (maintains a constant feed rate on the 'A' axis).
2. Maintain a constant total feed rate on the 'A' and 'X' axes.
3. Maintain a constant total feed rate on the 'A', 'X' and 'Y' axes.
4. Maintain a constant fibre speed (not yet implemented).
Winding speed
This is set in one of the dialogue text windows. For most machines this will have units of mm/min. The default value is the start feed from the .SM file. This winding speed is used in different ways depending upon the feed option selected.
For option 0 the value entered is the value that will be specified at the top of the NC sub program.
For option 1 this will be the speed of the mandrel axis. Exceptionally on a few customer configurations this is the mandrel surface speed at the largest mandrel diameter.
For options 2 and 3 the feed rate is calculated such that the combined feed to the relevant axes is equal to the value entered. Total feed for a set of axes is usually calculated by summing the squares of the incremental motions on each axis and then taking the square root. For option 3 this is as follows:
1
For option 4 the winding speed is the rate at which the fibre is deposited on the mandrel.
Please note that the machine will have a maximum feed rate value that can be used. This should be set in the .SM file. If this value is exceeded during feed rate calculations the feedrate will be set to this maximum value. The option and speed selected will effect the smoothness of machine motion and the total time required to wind the part. An indication of total winding time is given in the NC data.
Starting speed
This is the speed used at the start of the program to move to the initial (tie on) start position. This is often a slow value. The default value is set in the .SM file