I've seen some that have each tool holder coded and read the holders in the
chain or carousel as it moves. The system has no idea where any of the tools
are but it does know the difference between an empty spot and one with a tool.
So when a tool is requested it just runs the carousel or chain in one direction
until the desired tool comes by the sensor. Then it swaps the current tool for
the one in that slot. Should something cause the changer to drop a tool the
system has no idea it's missing. It will just throw a not found fault the next
time that tool is requested.
It's a slow way to change tools but less complicated to setup since the
operator doesn't have to log where the tools are, but the individual tool
characteristics have to be setup, same as with any changer system.
The fastest setup would be a system that has coded holders that can be stuck
into the carousel or chain anywhere, then the system runs the changer around
once, logging where each tool is. That would also require hardware to uniquely
identify each tool slot. For a high capacity changer, tools could be grouped by
job or by function. That would also allow for bi-directional movement to speed
up changes even more.
If the changer is uni-directional, then install the tools in the order they'll
be used and try to minimize needing to go back to a previously used tool. For
very time critical jobs, install more than one of the same tool so the changer
never has to run a full circuit to get back to a previously used tool. Ie, if
the second tool used is a 1/4" drill then two changes later the 1/4" drill is
needed again, install a second 1/4" drill. Save time and wear and tear on the
changer chain or carousel.
On Sunday, January 6, 2019, 10:32:42 AM MST, Jon Elson
<[email protected]> wrote:
There are two types of tool changers, fixed position and
random position. The fixed type generally have some kind of
one-at-a-time mechanism, so no pre-prep is possible.
When the tool is to be changed, the tool in the spindle is
placed in the magazine, the magazine is moved to the
new-tool position and the new tool is loaded. A typical
system is a tool carousel that is moved toward the spindle
and the tool is exchanged directly to/from the carousel,
with no arm.
A random tool changer swaps the previous tool with the new
one, putting the previous tool into the same holder as the
new tool came from. This requires the system to keep track
of what tool is in what position of the magazine. System
crashes may require reloading the tool table with what tool
is in what pot. The random changer requires some kind of
double-ended changer arm, so the current tool and the new
tool can be exchanged between magazine and spindle. This
system allows the magazine to be positioned to the new tool
before the actual tool change is performed. You just
program a T## to pre-select the tool at some point in the
program. This causes the tool carousel/chain to position to
the new tool. When you program M6, the tool is actually
swapped.
Jon
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