In horizontal machining center work, manual loading and unloading usually consists of:

• Pick the blank
• Locate the part on the pallet or fixture
• Push the pallet into the machine
• Table index and clamp
• Machining wait
• Pallet out
• Remove the finished part from the pallet
• Clean the pallet and fixture

When the cycle is stable, the part range is fairly uniform and the machine runs for long stretches, those repeated motions can be joined by an automation system. The machining characteristic here is many operations per part and long machining times, which is what makes pallet exchange with off-machine clamping worthwhile — which is exactly what makes the repeated motions worth fixing.

Taking DMG MORI as the example: DMG MORI was formed by merging DMG and MORI SEIKI; its horizontal range is the NHX series with the DMU series covering five-axis work, and the group already supplies automation and pallet systems of its own.

The system does not simply put a robot where an operator stood. It makes the following run in a fixed order:

1. Feeding
2. Picking
3. Clamping
4. Machining
5. Unloading
6. Collection

Add automated part storage and frequent manual replenishment turns into:

1. Storage buffer
2. Automatic feeding
3. Robot picking
4. CNC machining
5. Finished-part collection

The concept for a DMG MORI horizontal machining center therefore has to be designed from the whole production cycle, not from a robot model number.

A typical automatic cycle can be designed as:

1. Blank in
2. Off-machine clamping station
3. Part located and pre-clamped on the pallet or fixture
4. Pallet buffer
5. Robot or gantry picks the pallet
6. Into the DMG MORI horizontal machining center pallet exchange position
7. Pallet pushed in and locked
8. Machine confirms the locked state
9. Table indexes and the spindle machines
10. Machining complete
11. Pallet out to the exchange position
12. Robot removes the pallet
13. Finished part collected or passed to inspection
14. Pallet and fixture cleaned and returned to the buffer
15. The next part enters the cycle

Each of those motions needs its own state confirmation, for example:

• Is the part located on the pallet
• Is the pallet locked
• Is the fixture clamped
• Is the pallet exchange mechanism at the safe position
• Has the machining program finished
• Was the finished part removed
• Are the pallet and fixture cleaned and reset

The robot enters from the side, through the pallet exchange position, so the exchange position, the table index radius and the column travel range all have to be confirmed in the design.

The stability of an automatic system comes from the interlocks between those states, not from robot speed alone.

01 Gantry robot loading and unloading

A gantry robot normally runs on a fixed path. It suits: machines that stay in position and stand in a row, a clear loading path, a fairly stable part range with continuous batches, a defined cycle, and one robot serving several machines. Typical structure: automated part storage → gantry robot → machine → finished-part collection.

02 Six-axis robot loading and unloading

A six-axis robot has a larger working envelope. It suits: handling motions that are complex or need the part flipped, several machines plus an inspection station, a wide part range with frequent changeover, and connecting deburring, washing or inspection. Typical flow: storage → robot → machine → robot → inspection or finished-part area.

03 Automated part storage and feeding

Automated part storage is the link that turns manual bar handling into buffering: blanks queue in the magazine and the robot takes them to the cycle, so replenishment becomes a scheduled batch job instead of a per-part one. It suits sites that want to lengthen the replenishment interval, a fairly uniform part range that can be supplied by tray or basket, night shifts or long unattended stretches, and several lathes sharing one feeding and collection route.

Choosing between them

The handling unit and the feeding method are two separate decisions: they can be chosen independently or combined.

When two DMG MORI horizontal machining centers have cycles, part sizes and a layout that suit shared feeding, the following can be designed:

1. Storage magazine
2. Gantry or robot
3. horizontal machining center 1
4. horizontal machining center 2
5. Finished-part collection

That forms one multi-machine automation cell. A one-to-two configuration has to be calculated on:

• The cycle time of both machines
• The robot pick-and-place time
• The door opening time of both machines
• The part weight
• The robot payload
• The robot travel
• The distance between the two machines
• The storage capacity
• The scheduling logic when both machines finish at the same time

Not every pair of machines can share one robot. If the two cycles differ widely, or the machines stand too far apart, the robot path, the buffering method and the feeding structure have to be re-assessed.

Whether a part suits automated loading is decided by the part first. Across the typical work of a horizontal machining center, the common candidates are:

Whether a specific part suits automatic loading has to be confirmed on size, weight, shape, material, cycle time, clamping method, locating datum and the pose it arrives in. A name such as "shaft" or "disc" on its own is not a conclusion.

In automated loading the machine fixture is a critical link. On a horizontal machining center the clamping form is the pallet with a purpose-made fixture, and the system has to consider:

• Pallet size and repeat location accuracy
• Fixture type
• Part locating datum
• Clamp confirmation
• Part-present detection
• Interference between the fixture, the table index and the column
• Space to remove the finished part
• Chip and coolant cleaning of the pallet underside

Typical working cycle:

1. Pick the part off-machine
2. Locate it on the pallet
3. Pre-clamp in the fixture
4. Pallet into the machine
5. Pallet locked
6. Lock confirmed
7. Table index and machining
8. Pallet out and cleaned

The machine only moves to the next state after the clamped condition is confirmed. Chip evacuation on a horizontal layout is good, but chip residue on the pallet and fixture underside has to be cleaned separately. Automated loading is therefore not simply "pick it up and put it in".

Neither option is automatically better; the shop decides.

The final choice also depends on the direction of the pallet exchange position, the table index range, the part weight, the cycle, the number of machines, the robot travel and the safety area.

A project lands on the shop floor when these are verified:

01 Part location

Whether the part reaches the pick-up position reliably.

02 Fixture

Whether the robot gripper holds parts in different states reliably.

03 Machine interface

Whether the robot and the machine exchange run states reliably.

04 Cycle time

Whether the robot cycle matches the machine cycle.

05 Exception handling

How the system pauses, resets and recovers from a failed pick, a machine alarm or a part that is not in position.

06 Safety

Safety door, light curtain, safety area, emergency stop, robot safety and the human-robot boundary.

07 Manual takeover

Whether an operator can step in quickly when the automation trips.

A stable automatic system is not only one that completes its motions in normal running: it is one that recovers safely and in a controlled way from an abnormal state.