MANUAL OR HYDRAULIC FIXTURES?
Chucking a part manually has always taken precedence for a number of reasons.
Manual Clamping is usually simpler…cheaper….more cost effective for most low volume parts… and requires very little maintenance. Therefore, based on these major reasons for using Manual Clamping, why then consider using Hydraulic Clamping?
Multi part Manual Fixture with each part individually clamped by the operator
Before deciding on using Manual or Hydraulic Clamping here are a number of factors to consider, review and assist in making that final decision….
Part Seating – First, what is the nature of the part to be gripped? The part’s configuration must be evaluated. It may not be conducive for Hydraulic Clamping because of datum locations or areas with little access to hold the part with a Hydraulic Clamp. In addition, some parts may require only hand loading to clear the clamping units and sit properly in the work nest. However, many Hydraulic Fixtures hold a number of parts and they are all clamped simultaneously.
Production – What is the daily volume of part(s) to be manufactured? For a small volume of work it would make no sense…and there would be no justification for using Hydraulic Clamping. Should there be a large volume to run, the load/unload time can be greatly decreased using Hydraulic Fixtures.
Automaton – Is automation included in the process? The part must be able to sit firmly on the Work Locators or in the Work Nest without manual intervention to hold the part while clamping. This may require some type of load assist device…as simple as a spring clip. Also, accessibility by the load device is required. Plus, an air blow-off to clear chips is recommended and some means to confirm that the part is seated at clamping to assure the piece is secure in the fixture and not loose providing a safety hazard.
Chip Evacuation – Is there a possibility of harmful chips piling up? Chips cause havoc many times. If hard piping is used, it will cause an area for chips to pile up and wrap around the piping. Royal Machine provides all the hydraulic flow within the tombstone and does not use hard piping for this reason. If not addressed initially, this may cause more time in the load/unload time that you wish to improve production.
Tool Path – Is the tool path inhibited? Hydraulic Clamps can take up a great deal of room, especially Swing Type Clamps which may inhibit the tool path and size of the tools you require to machine the part. Larger parts may require larger Clamps to provide the required gripping forces. In turn, sometimes leading to complications in the design and not allowing sufficient room for machining.
Changeover – Is going from one part to a different part an issue? Moving of the clamping areas is not very feasible or recommended. It increases the chances for hydraulic leaks. Most Hydraulic Fixtures are dedicated to a particular part. This is not always the case. With some thought, it may be possible to cover a number of parts with the same set-up.
Costs – In the manufacturing of the Work Nests and Plates, Hydraulic Fixtures are more costly than Manual Fixtures. Hydraulic Clamping Cylinders are more complicated and the Hydraulic unit alone may add up to an additional $4,000.00. And, keeping hydraulic fluid clean of contaminants requires additional maintenance…plus, Check Valves, Sequence Valves, Accumulators are also required.
The Advantages – Hydraulic Clamping offers consistent clamping of the part in each cycle… as opposed to having the time consuming process of having the operator tighten the part each time. On thin parts the possibility of distortion is greatly reduced…and finally, Hydraulic Clamping allows clamping more than one part at a time…obviously improving load/unload time.
Multi part Hydraulic Fixture complete with Check Valves, Sequence Valves, and part load confirmation
As mentioned in the beginning of this article, there are many factors to review and consider…the final decision of selecting Manual or Hydraulic Fixtures is yours…based on your specific requirements.