Flexible Tooling Fixture Equipment

Specification for shaft workpiece TA-20/270 TA-35/270 Diameter Φ10 ∼ Φ80 mm Length 200 ∼ 800 mm Max. Weight 14 kg（Should not be unbalanced） 25 kg（Should not be unbalanced ） Note : The maximum length of the material depends on the distance between centers, the door opening area, the chuck and jaws. Diameter difference between material and finished workpiece is within 18mm at the maximum. Please contact us for further information.

To use thin wedges of metal to adjust fixtures, i.e shimming, has been a common approach to achieve desired position and tolerance. To build a fixture using shims is time-consuming and results in a fixture that is difficult to modify. The newly developed ART (Affordable Reconfigurable Tooling) concept addresses the need for flexible fixturing by means of reconfigurable supports that are set to desired position by guidance from an outer measuring system. The ART concept can be realized by means of several different reconfigurable devices, among these is the newly developed “Mini Flexapod”. This small 6 degree of freedom reconfigurable device was designed to eliminate shimming and therefore has a small working envelope of approximately 4x4x4 mm. The Mini Flexapod is a result of working with several manufacturing cases  described in this paper.

In order to survive in today’s global market many manufacturing companies seek flexibility to reduce product lead times and meet changing market demands. Manufacturing equipment forms the base of the production system and manufacturing technology with the capability to adapt to any changes in prerequisites is thus a key enabler of flexibility. Industrial robots and fixtures are common in all types of manufacturing. Robots are versatile re-programmable units capable of performing many tasks, such as welding, part transfer, etc. Industrial robots have traditionally been unable to handle disturbances and lack of constraints of input. This has led to manual operations often being preferred to automation when some level of flexibility is needed. One way to enhance manufacturing equipment’s capability to handle unknown events is to integrate different kinds of sensors to gain more knowledge of the manufacturing environment. Force sensors, for example, can be used to close the feedback loop and, together with an adequate control system, enable the robot to react to force stimuli. This is useful in manufacturing applications like assembly and deburring, which have previously been difficult to automate.

This thesis explores how common manufacturing equipment, like industrial robots and fixtures, combined with sensor input, can enhance flexibility in manufacturing. The research shows that force-controlled robots, reacting to force stimuli, produce consistent results in assembly of compliant structures and in complex deburring. Force control also makes the system more robust, as it is able to handle variance in the assembled and deburred parts which adds to system flexibility. It also lessens the need for accuracy in other equipment used, such as grippers and fixtures, and makes programming easier and safer. Force control would, however, benefit if parameter tuning was simplified in order to fit an industrial environment and if presented user information is tailored for the intended user.

Genom att använda mätsystem tillsammans med fixturer har nya fixturenheter till ART utvecklats. Dessa enheter minskar resursåtgången vid sammanbyggnad och omkonstruktion av fixturer. De öppnar även för att aktiva fixturer som är mer lika robotar, men som fortfarande är kostnadseffektiva. ART påverkar också design av fixturer positivt, eftersom stödjande mjukvaruverktyg för design kan tas fram.

Fixturer är enheter som håller en produkt i önskat läge under tillverkningsprocessen. En fixtur har traditionellt konstruerats för att passa en produkt och en process. De har således inte kunnat användas t.ex. för olika produkt-typer eller när produkter förändrats på något sätt, vilket har påverkat systemets flexibilitet negativt. Sensorer, som t.ex. olika mätsystem kan användas för att frikoppla en fixturs struktur från dess interna noggrannhetskedja, något som annars är ett vanligt sätt att uppnå önskad noggrannhet i fixturen. Det tidigare utvecklade ART konceptet (Affordable Reconfigurable Tooling ungefär Kostnadseffektiva Rekonfigurerbara Verktyg) bygger på denna princip. ART fokuserar på att öka flexibiliteten för fixturer samtidigt som de fortfarande är resurseffektiva.