Engineered Workholding Fixtures

John Hart leverages 70 years of practical understanding of machine tools to design and build engineered workholding fixtures that produce unmatched efficency gains and precision.
John Hart specializes in developing turnkey machining solutions that significantly boost productivity, offer safer operation and facilitate automation in more complex setups.

 

 

We have a wealth of experience covering the installation of workholding fixtures onto customer’s machines, working closely with tooling companies, programming the components and completing the CNC fixture and tooling run off to a specified CpK.

These capabilities allow us to offer full turnkey machining solutions to our customers and our team of designers, machinists, engineers and production managers will be involved every step of the way until the job is delivered, on time and on budget.

 

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From customer consultation, to 3D CAD design, animation, tool interference checking, CNC fixture manufacturing and functional testing, through to full run-off on your machine tool including statistical process analysis, we can do it all.
Process Planning

workholding fixtures process planningJohn Hart engineers have a great depth of experience in advanced CNC machining techniques, efficient cutting strategies and rigid, repeatable CNC workholding solutions.

Using this experience, John Hart project engineers will sit down with the client to discuss the required project outcomes in order to tailor a customized turnkey manufacturing solution.

At this time, the following will be formulated and presented to the customer for further discussion:

    • Detailed machining time study proposal which outlines projected cycle times and number of CNC machines required for required production volumes
    • Conceptual 3D work holding proposal
    • Projected project time line

It is at this stage that the details of each important element of the project are discussed and mutually agreed upon by both the customer and John Hart engineers.

Project Planning

workholding fixtures project planningUpon completion of the Process Planning stage, John Hart engineers will prepare a detailed project time line projection for the clients’ approval.

John Hart Technology has the resources and experienced engineering team to undertake responsibility for the entire turn-key project on the clients’ behalf, delivering the client a production ready manufacturing cell.

The key components of a typical turn-key project are:

    • Liaising with CNC machine tool vendors on technical and timing details
    • Management of CNC cutting tool vendors from process concepts through to production ready cutting tool delivery
    • Design, manufacture and supply of rigid, repeatable CNC workholding solutions
    • CNC machine programming
    • Installation and commissioning of CNC workholding fixtures on machine tools
    • Run-off and capability testing of clients’ process

Each of these components are carefully included in the overall project plan by John Hart engineers using a wealth of turn-key project experience, particularly on automotive projects.

Design

workholding fixtures designUpon commencement of the design stage of a project, John Hart design engineers will create CNC workholding concepts in 3D which are tailored to the specific requirements of the client. These concepts will be presented to the client for feedback and approval before the final design begins.

Using the feedback from the client, John Hart design engineers will create a final CNC workholding design ready for manufacture. During the final design, the following key items are factored in.

    • Maximum rigidity by design, clamping forces and positions are carefully calculated
    • Internal hydraulic porting to ensure a clean and tidy design which reduces unnecessary swarf build up on the CNC fixture
    • CNC cutting tool clearances checked in 3D before manufacture to avoid complications further into the project where the timing impact is far greater
    • Most effective clamping sequence for secure and accurate part clamping
    • Quick and cost effective replacement of any consumable items such as datums and clamping points
    • Modular CNC fixture design to allow for flexibility in manufacture
    • Pneumatic part presence sensing to ensure parts are clamped securely and accurately

The final design will be submitted to the client for further feedback and approval prior to final manufacture release.

Cutting Tools

workholding fixtures cutting toolsOne of the most important components of a successful turnkey machining project are the CNC cutting tools.

With a long and diverse history of successful CNC machining turnkey projects working together CNC cutting tool suppliers, John Hart has built strong technical partnerships with the worlds largest cutting tool organisations.

With the strength of these partnerships John Hart is able to work closely with their design and engineering teams to ensure all bases are covered before the CNC cutting tools and CNC fixtures are manufactured. This translates into the most time efficient result once on the clients site.

As we conduct full cutting tool and fixture interface checking in the 3D space during the CNC fixture design phase, the following can be achieved:

    • CNC cutting tool interference avoided completely
    • CNC cutting tools can be designed to be as short and rigid as possible
    • Both the CNC fixture and CNC cutting tools can be altered and checked prior to manufacture allowing the best and most effective tooling choices to be made from the beginning
Build & Test

workholding fixtures build and assemblyUpon commencement of the build and test phase of the project, John Hart project engineers carefully select component manufacturers from our database of quality suppliers of CNC machining services. John Hart engineers work closely with these suppliers from the kick-off meeting through to final quality inspection to ensure that both our strict delivery and quality requirements are achieved.

Once all components are delivered to our purpose-built assembly and testing facility, John Hart engineers inspect, assemble and thoroughly test the final product with these key areas of focus:

    • Hydraulic system tested under rated pressures for an extended time to guarantee system integrity
    • CNC fixture tested on 3D measuring machine to ensure required assembly accuracy is achieved
    • Clamping and support elements tested for desired functionality
    • Clamping and support elements set as calculated pressures to suit application
    • Clamping and support elements set to desired sequence by built-in sequencing system
    • CNC ixture tested with clients castings/components for accuracy and rigidity

A final quality check is the undertaken where all CNC fixture components are re-tensioned prior to the fixtures being packed in secure, custom built boxes ready to ship to site.

CNC Programming

workholding fixtures cnc programmingAll John Hart engineers have been trained in advanced CNC programming. This allows us to supply CNC programming services that are not only modular and easy to understand, but include additional features such as:

    • The ability to easily move the entire process to another CNC machine tool if required with minimal production downtime
    • The ability to automatically monitor cutting tool length settings within preset limits to avoid operator related tool collisions in production
    • The ability to quickly and easily modify cutting data in one easy to understand screen
    • The ability to quickly and easily modify positional co-ordinate information in one easy to understand screen

All CNC programs will be compiled at our facility prior to commissioning and will utilize the 3D designs previously created in the design phase to carefully calculate the most efficient tool paths to ensure the best possible productivity.

Commissioning

workholding fixtures commissioningAt the commissioning stage of the project, John Hart engineers will visit the clients site to complete the installation of CNC fixtures, CNC cutting tools and CNC programs to the machines. Our engineers will train the clients’ engineering staff in:

    • Correct and accurate installation and positioning of the CNC fixture as planned in the design stage
    • Plumbing of hydraulic lines to the CNC fixture
    • Connection of pneumatic lines to the CNC fixture
    • Final testing the of CNC fixture for both hydraulic clamping and pneumatic part presence sensing

John Hart engineers will then load the previously prepared CNC machining programs and the appropriate cutting tools to the machine tool.

Process Capability

workholding fixtures process capabilityProcess Capability is the final stage of the project and, when completed, marks the readiness of the CNC machining cell to begin production. With many years of experience with process capability, John Hart engineers will proactively lead the client through this critical process with a goal to complete the required process testing in a most efficient and timely manner.

During this stage, John Hart engineers will work proactively with both the clients’ engineering and quality personnel, and the cutting tool vendors’ support staff to consolidate each individual party into a team with a common directive.

The typical process capability consists of:

    • Proving out of CNC programs
    • Cycle time enhancement
    • Dimensional targeting
    • First part submission to quality engineers for 100% inspection (often known as ISIR)
    • A small batch test run of parts as an initial indication of process capability (often known as a mini CpK)
    • A final capability study (CpK) with a large run of parts under production conditions (clients’ machine operators, full machining rates etc.)
    • Finals reports prepared detailing the capability of the process to begin production

Once all capability testing criteria have been met or exceeded, production can commence.

John Hart engineers will then complete training of the clients operator and maintenance staff and prepare the final documentation of the process for submission to the client. This marks the completion of the project.