Clamping Devices / Milling Fixtures
After the forming process, clamping devices / milling fixtures are an essential component of automated milling operations using CNC machines. The fixture matches the part geometry and typically holds the workpiece in place using a vacuum.
Basically, two types of clamping devices can be distinguished: conventional vacuum clamping devices – often referred to as hard tools – and universal clamping devices.
.jpg)
Comparison of conventional vs. universal
The precise positioning of the components on the fixture is extremely important for the quality of the machining process. In most cases, features are attached to the component (holes, recesses, precise stops, etc.) which then find their counterpart on the fixture.
Conventional clamping device
-
Simple positioning
-
Positioning element is an integral part of the fixture
-
High repeat accuracy
Universal holding fixtures
-
Positioning is a particular challenge
-
Suction cup positions are only suitable to a limited extent, as they are at fixed grid points
-
Auxiliary elements such as adjustable adapters or tools are necessary
-
Exception: MICADO OCTOPUS with individual positions
Conclusion:
Conventional fixtures are indispensable when the machining process requires almost full-surface clamping and/or the geometries to be clamped are very complex.
However, if this is not the case, universal fixtures can offer significant advantages and significantly strengthen the competitiveness of the manufacturing company!
Comparison of conventional vs. universal
The precise positioning of the components on the fixture is extremely important for the quality of the machining process. In most cases, features are attached to the component (holes, recesses, precise stops, etc.) which then find their counterpart on the fixture.
Conventional clamping device
-
Simple positioning
-
Positioning element is an integral part of the fixture
-
High repeat accuracy
Universal holding fixtures
-
Positioning is a particular challenge
-
Suction cup positions are only suitable to a limited extent, as they are at fixed grid points
-
Auxiliary elements such as adjustable adapters or tools are necessary
-
Exception: MICADO OCTOPUS with individual positions
-
There are many factors that influence milling quality. The machine and milling tool, as well as the cutting parameters used, are the most important factors. Nevertheless, the clamping device also has a significant influence.
Conventional clamping device
-
Highest possible machining speeds
-
Large-area clamping prevents vibration and deformation
-
Clamping surface close to the milling edge required
-
Protruding parts must also be clamped
Universal holding devices
-
Fixture highly relevant to the process
-
Few clamping points / small contact surface
-
Risk of deformation and vibration
-
Springback during drilling and vibration leads to chatter marks or delamination
-
Close coordination of fixture and milling parameters is necessary for a good and stable process
-
Net milling times refer to the times of an entire post-processing process for fibre composite components during which the milling machine is in cutting engagement. It should be noted here that, especially in the aviation industry, batch size 1 is usually used. This means that two identical parts are never milled one after the other, but are always considered in ship sets. A shipset contains all the components that will later be needed for the assembly of a module.
Conventional clamping device
-
Höchste Bearbeitungsgeschwindigkeiten möglich
-
Großflächige Aufspannung verhindert Vibration & Verformung
-
Spannfläche nahe an der Fräskante erforderlich
-
Auch Überstand muss mitgespannt werden
-
Low net milling times due to frequent retooling
-
Two working areas within the milling machine reduce downtimes
-
Alternatively, pallet systems can be used for external set-up
Universal holding fixtures
-
No device change necessary – only automatic “reconfiguration”
-
Configuration time: a few seconds to approx. 20 minutes (depending on the concept)
-
No handling of heavy devices necessary
-
No storage space required
-
Eine hohe Verfügbarkeit der Vorrichtung ist Voraussetzung für eine sichere Produktionsplanung. Dies ist stark von Komplexität und Qualität der Ausführung abhängig.
Conventional clamping device
-
Low risk of production downtime as individual fixtures are available for each component
-
Repairs and maintenance can often be carried out internally
Universal holding fixtures
-
Failure risk depends on complexity and quality
-
Many servo motors = high risk
-
Passive systems are significantly more fail-safe
-
Spare parts stockpiling strongly recommended
-
Quick response necessary in the event of downtime
-
Costs are divided into investment and operating costs. Only by considering a specific service life can a valid comparison be made.
Conventional clamping device
-
Higher acquisition costs / components
-
Additional costs due to warehousing
-
Manipulation and handling increase expenditur
Universal holding devices
-
Usually lower acquisition costs per component, especially for large parts
-
Low storage costs
-
Significantly accelerated process
-
Conclusion:
Conventional fixtures are indispensable when the machining process requires almost full-surface clamping and/or the geometries to be clamped are very complex.
However, if this is not the case, universal fixtures can offer significant advantages and significantly strengthen the competitiveness of the manufacturing company!
This is your Testimonial quote. Give your customers the stage to tell the world how great you are!
FACC (Österreich)
This is your Testimonial quote. Give your customers the stage to tell the world how great you are!
Fooke GmbH (Deutschland)
This is your Testimonial quote. Give your customers the stage to tell the world how great you are!
Sonaca (Belgien)
This is your Testimonial quote. Give your customers the stage to tell the world how great you are!
FACC (Österreich)
This is your Testimonial quote. Give your customers the stage to tell the world how great you are!
Fooke GmbH (Deutschland)
This is your Testimonial quote. Give your customers the stage to tell the world how great you are!
Sonaca (Belgien)
