Machine terminology help

[jcnewbie]

Can someone please explain me the meaning of the following terms, with examples if possible.

1. gantry
2. nutating
3.gantry
4. Table / Table
5.Head / Head

Thanks in advance !

[Mike Mattera]

Gantry machine has the head mounted on a rail, supported on both side of the table. You see this in lots of routers. To to the Thermwood web site.

Nutating head or Table means that it's a 2 axis head or table, where the pivot point is at an angle. Look at Deckle Maho DMG web site for their 5 axis machines

Head/Head means that both rotary axis (on a 5 axis machine) are in the head (C & B).
Table/Table means that both rotary axis (on a 5 axis machine) are in the table (A & C).

You can also have a head/table.

Mike Mattera

[jcnewbie]

Thanks for the info.

One more question if I may ask.

What is the difference between the words "rotating" and "indexing" a table.

[307startup]

Indexing is a defined movement, stated in degrees of rotation, or angular movement. Typically with an indexer, there are plates that attach to the rear of the device that will only allow positive movement when a pin is released and re-engages in a specified hole in the plate.

Rotating is a defined movement, stated in degrees of rotation, that can be continuously turning, or movements greater than 90*.

For example, you have a 4" workpiece chucked in your rotary table, and need to drill 6 holes about the circumference. You could index the table 60 degrees, with a stop for each operation, before being re-engaged for the next operation.

OR...

You have a 4" workpiece chucked in your rotary table, and need to engrave a serial number and company logo around the circumference. You could use full-rotary mode to engrave these on your workpiece using specified moves, usually implemented by a program generated by CAM software, that choreographs the various axes movements.

[psychomill]

I think it's simpler to say that generally...

Indexer (Indexing): Is a positioner. Which means the mechanics will only allow the head or table to position at specific angles. For example: 5° increments only, nothing in between. On CNCs, this is also a rapid motion only. No feed commands are effective so you generally do not program a cut while the table/head is in motion.

Rotatary (Rotating): Allows an "infinite" range of motion and can be programmed to cut while in motion and maintain accuracy.

So with said, you can make a rotary index, but you can't make an indexer be a rotary.