Optical Path

The optical path is the path that is traveled by the laser beam between its point of entry into the frame of the high speed cutting center and the point where it leaves a nozzle placed after the focusing lens.

The beam enters from one side of the movable gantry.  It then reaches a totally reflecting mirror angled 45� with respect to the surface of the object carrying platform.  The mirror is installed in a three dimensional adjustable device which sets the vertical direction of the beam on the focusing lens placed at the base of an optical guide.

The focusing lens is placed in a work head.  The nozzle from which the beam emanates is located at the bottom of the work head.

Once the laser beam enters the laser center it encounters 3 optics (2 mirrors and 1 lens).

The inside space separating the focusing lens from the tip of the nozzle is protected by a pressurized assist gas that flows from the nozzle.

The work head is installed on an automatic profile tracking device which ensures a consistent focal distance (between the lens and the surface of the material).

The entire optical path can be pressurized to prevent the entry of gases that would contaminate the mechanical and optical components.  Depending on the power of the laser, it is possible to cool the optical  components placed along the path of the beam to protect them against any excessive heating.

The machine is supplied with total reflection mirrors and focusing lenses.

The unit is supplied with accessories for setting the alignment between the laser beam and the optical axis of the machine.

Structure

The primary structures of the CF 1500 Cutting Center are made of thermally stabilized welded material filled with a composite material that makes the machine up to 2 times more rigid than if it were made of an equal weight of cast iron.

Sliding Doors with Safety Interlocks

The machine is equipped with two sliding doors at the front of the machine.  Each door is equipped with a safety interlock switch.

Y Axis Motion Guides

Precision ground, hardened steel ways (NSK) having a rectangular section are used to support all the axes.

The ways are protected from impacts and contamination by using metal shields or bellows.  The motion guides can be placed in a slightly pressurized enclosure to protect them against certain aggressive environments.

Axis Drive

All the axes are driven by Siemens AC digital servo drives using digital linear motors on the X and Y axes and an AC servo motor for the Z axis.

The drive motors are installed so that mechanical play is eliminated when changing the direction of movement along the axis.

Position control along the axis is performed in a closed loop through the numerical control system connected to a linear optical measuring system, which has a resolution of .5 micron.

The acceleration rates along the axis can be programmed and can produce a linear speed of 6700"/min with acceleration rates of 10m/s².
 

Automatic Focusing, Non-contact Cutting Head

The machine is equipped with an automatic focusing system in the cutting head.  It offers the possibility to adapt the focal point of the laser beam to the application during the automatic cycle.

Due to the changing length of the laser beam between the Laser source and the focusing lens, the focus point will change when the machine is moving from one end-position to the other.  The AFC - system offers the possibility of 'Dynamic Focal Control', which will, accordingly to the length of the beam path, adapt the focus point continuously.

• Lense cartridge for quick change
• Anti-splatter window
• Collision protection of the cutting head
• Auto tracking system

Bellows protection of beam path - equally pressurized

The pallet changer transfers the cutting table from the cutting area into the changer so that it can be unloaded and transfers second (loaded) pallet from the changer into the cutting area.

• Cutting pallet is always at same height for cutting

• Pallet change cycle is programmable - fastest cycle is 28 sec's.

The ball support allows for easy      
 positioning of material when loading.

1  Cycle 1

Pallet 1 is clamped in the machine and pallet 2 is clamped in the changer on the lower level of the lift.  The lift is up.

• When pushing 'Change pallets' the lift in the changer is moving down.
• The pallet clamps in the changer and in the machine are opened.
• The pallet on the machine is transferred to the changer (on the upper level of the lift).
• The pallet clamp is activated.
• The lift is going up and the lower pallet (new pallet) is locked by the chain.  The pallet clamp is opened.
• The new pallet is transferred to the cutting area.  The clamps on the machine and in the changer are activated.
• The lift is going down, the pallet on the changer is now on unloading level.

 
2  Cycle 2

Pallet 2 is clamped in the machine and pallet 1 is clamped in the changer on the upper level of the lift.  The lift is down.

• When pushing 'Change pallets' the lift in the changer is moving up.
• The pallet clamps in the changer and in the machine are opened.
• The pallet on the machine is transferred to the changer (on the lower level of the lift).
• The pallet clamp is activated.
• The lift is going down and the upper pallet (new pallet) is locked by the chain.  The pallet clamp is opened.
• The new pallet is transferred to the cutting area.  The clamps on the machine and in the changer are activated (both pallets are clamped).
• The lift is going up, the pallet on the changer is now on unloading level.

Safety System at the Pallet Changer Area

The area around the pallet changer is guarded by a safety system (radar).  This system makes sure that the pallet movements can't be activated when somebody is too close to the system.

Hydraulic lifters for pallet

Scrap is collected by a part collector (exhaust funnel) and falls on a conveyor belt.  The conveyor belts are pulling the scrap out of the machine.

Each conveyor belt is equipped with a current monitoring relay and with a motor protector.  An over-current or an overload on the belt will automatically switch off the conveyor belt and will generate an error message.

• Siemens 840 D Control
  • 11" TFT Color Screen
  • RS 232 Interface
  • 1.4 Mb Ram
  • 500 Mb Hard Disk
  • Multi-Tasking
  • Graphic display of NC Program
  • 3.5" Floppy Disc Drive

Features of Cutting Library

A table of the cutting library contains the following fields:

• the MATERIAL name
• the THICKNESS of the sheet material

this information comes on top of the page, just below the title.  Further information is organized in a total of seven columns:

• the drill parameters (DRILLING) for three steps
• the side blow parameters (SIDE BLOW) and
• three sets of cutting parameters (PROCESSING).

Balliu has revolutionized laser processing of thicker materials with the introduction of its unique side blow method of piercing (patent applied for).  While the side blow or power pierce method has been around for some time, it has never really lived up to its full potential.  Balliu has managed to industrialize this technology with CNC controls that deliver a quick, clean and reliable method of piercing steel.

What does the side blow method do for the overall laser cutting process?  Put simply it means that all thicknesses of mild steel can be pierced in under 1.5 seconds.

Consider cutting a component in 12 mm mild steel that requires 6 pierces (i.e. 5 internal holes and the external profile).  Assume that we require 60 seconds to cut the profile.  Also let us be optimists and assume it takes 7.0 seconds to pierce 12 mm using conventional techniques.  Lets look at the results.

This gives a 34.2 second advantage to the side blow method.  On this simple example, this means a 33.5% overall reduction in cycle times, just by changing the method we pierce.

• A great deal of heat input
• Can damage Lens
• Leaves a pool of slag which interferes with height following
• Is quick and useful on thinner metals, but is not an option over 3 - 4 mm

• Minimal heat input
• Super pulse can cause less damage from back splatter
• Makes a small, neat start hole with no surface slag
• Takes a relatively long time to pierce (approx. 0.75 seconds per mm thickness)

• Quickest of all piercing methods
• Can pierce 12 mm in 1.5 seconds
• Reduces damage to the lens from back splatter
• Removes most surface slag  with a cooling gas

Three cutting gasses at normal pressure (9 bar max.), and one at high pressure (20 bar, according to the lens) can be connected to the machine.  These four gasses are connected directly to the valves in the cabinet valves.  All the gas tubes are marked.  The tube numbers are mentioned on the schematic GS1.

Purge Circuit for the optical path

Description of the purge circuit
A gas circuit is protecting the optical path against dust.  The gas supply for this circuit is derived from the GAS 1 (NITROGEN) circuit.

During an X- or Y-axis travel, a gas stream is blown under the bellows.  This stream is creating an over-pressure in the optical path and this is preserving dust to fall down.  The gas stream starts at the moment the X- or Y-axis motion is commanded and stops 10 seconds after the motion stopped.  A parameter that can be accessed through the user software allows the activation of the purge circuit together with axis.

Water circuit for the optical parts

The bending mirrors, the telescope and the lens are water-cooled.  This cooling is preserving the optical parts from damage due to an excessive heat concentration on the surface.

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