ROBOTIC DEBURRING, FETTLING & DEFLASHING
Deburring of Aluminium PDC components is time consuming, hazardous and tiring for operators. It is very difficult to match the output of PDC machines with manual fettling. This is where robots come in. For high volume components, 6 axis robots with compliant deburring spindles and tungsten carbide burs are used for removing the excess material from the component.
The quality of castings needs to be good and the parting line flash thickness and length should be consistent. If there is consistency, robotic deburring can drastically improve the productivity and significantly reduce the dependence on labour. Inventory costs will also come down as the components can be delivered to customers faster.
A variety of high RPM pneumatic deburring spindles are available with both axial and radial compliance. Compliant grinding wheels are also available for removal of thicker gates. Linishing tools can also be added. Tool selection is highly critical to ensure the success of deburring projects. Runner riser cutting can also be accomplished with robots.
Deburring can be accomplished by two means. Option 1 is where the deburring tool is mounted on the robot and the component is located in a fixture. In this case, if multiple tools are to be used for deburring, tool changers can be used to pick up 2 or more tools. Option 2 is where component is handled by the robot and deburring tools are mounted on pedestals. This is a cost effective method.
Grey and SG Iron casting fettling is a mandatory operation prior to machining. This process is very labour intensive and hazardous. The dust generated during grinding and the risk of injury during long hours of fettling poses a serious health hazard. If in house fettling capacity is insufficient, components have to be sent out to third party suppliers for fettling. This non value added transport and loading/unloading process increases the cost per component. The inventory cost also adds up.
High payload foundry specification robots can be utilized to effectively fettle castings. The robots can run 24/7 and provide consistent results.
For smaller components, the robots can grip the components and present them to pedestal mounted grinding wheels. These special wheels are diamond coated for long life. The grinding unit is mounted on a pneumatic compensation unit. This is provided so that the robot does not get overloaded in case the runner/in gate material is excessive. For tight profiles and parting line flash removal smaller, milling cutters with indexable inserts can be used for material removal.
We have bulk in feed systems such as slat chain conveyors where an hour’s supply of components can be loaded. Vision systems can be utilized to locate the component and identify the location of the runner/in gate material to be removed. This eliminates the need for an operator to be present near the cell for loading/unloading. One operator can man multiple cells. This type of in feed system is suitable for smaller diameter circular components. Typical fettling times for these components are less than a minute.
For other complex shapes, simple laser cut fixtures mounted on indexing or rotary tables can be used for component in feed. These require frequent loading and the presence of a full time operator.
For heavier components, the components can be fed to the robots using a turntable or slide table. The component is fixtured in place. A robot mounted high speed HSK spindle can be utilized along with an array of tools mounted on a tool changer or rotary indexer. Typical cycle times are more than 3 minutes for these components due to the complexity and multiple tool changes required.
All our systems come standard with safety fencing and interlocking gates. Optional dust collection systems and sheet metal enclosures can be provided to reduce noise and dust.
Machined Component Deburring
High precision components processed on VMC’s and HMC’s tend to have sharp edges after machining. Drilled holes that open up on the inside of the component require precision deburring.
Gears require precision deburring after the hobbing process is completed. Deburring is a critical process as the geometry of the component should not be altered. Only the burrs projecting should be removed.
Repeatability and precision are 2 key features required for deburring. 6 axis robots provide just that. Deburring requires brushes, embedded wheels or tungsten carbide burrs. Tool wear and tear is inevitable during the deburring process. Automatic compensation offsets can be provided on the robot programs after the wheel wear pattern is established. Sensors and probes can also be used to measure the wheel diameter periodically and program offsets can be based on the diameter values.
Pneumatically actualled collets are available as an option on some of the deburring spindles. When the wheel diameter reduces beyond a certain value, the bur or tool can be automatically exchanged for uninterrupted production.