--- title: Custom Assembly Press with Press-Fit Validation | Case Study description: How Liberty Automation engineered controls for a custom assembly press that validates force and depth on every insertion and locks failed parts for quality. image: https://www.liberty-automation.com/hubfs/Custom%20Assembly%20Press%20with%20Press-Fit%20Validation.png --- [Go Back Up](https://www.liberty-automation.com/news/case-studies/custom-assembly-press-press-fit-validation#top) [Skip to Content](https://www.liberty-automation.com/news/case-studies/custom-assembly-press-press-fit-validation#body) ![marker\_02](https://www.liberty-automation.com/hubfs/marker_02.svg) **4890 N 150 E Albion, IN 46701** [![liberty\_automation\_logo\_horizontal\_color](https://www.liberty-automation.com/hs-fs/hubfs/liberty_automation_logo_horizontal_color.png?width=300&height=82&name=liberty_automation_logo_horizontal_color.png "liberty_automation_logo_horizontal_color")](https://www.liberty-automation.com) Toggle Menu - [Services](https://www.liberty-automation.com/services) Toggle children for Services Main Menu (Press to Return) \> Services - [Inspection & Gauging](https://www.liberty-automation.com/inspection-gauging-systems) - [Custom Equipment](https://www.liberty-automation.com/custom-equipment) - [Quality Control & Data Collection](https://www.liberty-automation.com/quality-control-data-collection-systems) - [Integration](https://www.liberty-automation.com/integration) - [Programming](https://www.liberty-automation.com/plc-hmi-programming) - [Control Panels](https://www.liberty-automation.com/control-panels) - [Partner With Us](https://www.liberty-automation.com/partner-with-us) - [Fit Call](https://www.liberty-automation.com/fit-call) - [About Us](https://www.liberty-automation.com/about-us) Toggle children for About Us Main Menu (Press to Return) \> About Us - [About Us](https://www.liberty-automation.com/about-us) - [News & Insights](https://www.liberty-automation.com/news) - [Contact](https://www.liberty-automation.com/contact) [back to blog](https://www.liberty-automation.com/news) # Custom Assembly Press with Press-Fit Validation | Case Study [Case Study](https://www.liberty-automation.com/news/topic/case-study) • Oct 19, 2026, 11:36:11 AM ![](https://www.liberty-automation.com/hubfs/Custom%20Assembly%20Press%20with%20Press-Fit%20Validation.png) Share article [mailto:?subject=Custom%20Assembly%20Press%20with%20Press-Fit%20Validation%20%7C%20Case%20Study&body=https%3A%2F%2Fwww.liberty-automation.com%2Fnews%2Fcase-studies%2Fcustom-assembly-press-press-fit-validation](mailto:?subject=Custom%20Assembly%20Press%20with%20Press-Fit%20Validation%20%7C%20Case%20Study&body=https%3A%2F%2Fwww.liberty-automation.com%2Fnews%2Fcase-studies%2Fcustom-assembly-press-press-fit-validation) ## **When a Press-Fit Looks Right but Fails Spec** How Liberty Automation engineered the controls for a custom assembly press that validates every press-fit as it happens, and later added a [quality](https://www.liberty-automation.com/quality-control-data-collection-systems) lock so a failed part can't leave the station ## **At a glance** - **Customer:** A Midwest production CNC machining company that supplies cast suspension components to a major automotive OEM - **The part:** Suspension casting – Each one gets two bushings and one pin pressed in, and each insertion has to meet spec for force and depth. - **Why Liberty was called in:** The customer was bidding on a new production program for this part. The plan called for a single custom assembly press that could install both bushings and the pin in one cycle and validate each press-fit for force and depth as it happened. A fabrication and panel-building partner was building the machine and brought Liberty in to consult on the controls and write the software. - **What Liberty delivered:** - **Phase 1:** Specified the processor, the I/O, and the strain gauge I/O used to measure press force. Consulted on the control design and wrote the full machine software. - **Phase 2:** Added a quality package. Every part is logged, and failed parts are locked in the machine until the quality department releases them. - **Timeline:** - **Phase 1:** About one week of startup, then roughly half a week of on-site production support. - **Phase 2:** About one week of development and two to three days to install, done while the line kept running. - **Outcome:** - All three insertions completed and validated in a single machine cycle. - Steady line rate of about two parts per minute. - A traceable press-force record for every part. - Quality control over every reject. ## **The situation** The customer, a production CNC machining company, was preparing to bid on a new automotive program: a front-suspension lower knuckle casting for a major OEM. The customer would machine the casting, then install two bushings and one pin before shipping. This was a new product line for them, so the assembly process would be built from scratch around this program. The requirement wasn't just to press the components to depth. Each pressed-fit had to be validated against an insertion-force window, because force is what confirms a proper interference fit. On this part, a bore that's slightly oversized can still be pressed to full depth and pass visual inspection. It just doesn't have the retention to stay put once the part leaves the building. Depth alone couldn't catch that. Force could. The plan was to handle all three pressing operations in one station and one cycle, with force and depth monitoring built into the controls. That avoided routing the part through separate press operations for each component, with the extra handling and labor that brings. It also had to suit a production floor running at automotive volumes. That meant a simple operator cycle, a clear pass/fail result on every part, and setpoints the customer's team could manage. A fabrication and panel-building partner who had worked with Liberty on earlier equipment projects was contracted to build the machine. They handled the mechanical build, the panel, and the electrical schematics. For the controls engineering and software, they brought in Liberty as a trusted partner. ## **Defining the right machine** The project started with a reference point: a machine already in production overseas for this kind of assembly. The early thinking was that a similar design would be the most dependable path, and Liberty received photos and all the available details on that machine. Reviewed against this program's actual requirements, the reference machine was clearly built to handle a much wider range of scenarios, and its cost and complexity reflected that. This program had one part family, defined tolerances, and a known production rate. Liberty worked with the fabrication and R&D team to separate what was critical from what wasn't. The critical items were: - accurate force measurement on every press; - depth measurement; - reliable pass/fail logic; - a repeatable operator cycle. Anything else that was more suited to scenarios this program would never see, was left out. The result was a machine engineered around the customer's actual application. It was simpler and less costly to build, and focused on the measurements that decide whether a part is good. ## **Where Liberty came in** Liberty's scope covered the decisions that set the machine's capability. The fabricator handled the panel build and schematics, and Liberty consulted in the overall [design](https://www.liberty-automation.com/custom-equipment). **Specified the control system.** Liberty specified the processor, the I/O, and the strain gauge I/O that measures press force, and consulted with the fabricator on the overall control design. Those choices set the machine's control and sensing layer. **Chose a platform with room to grow.** The controls run on an embedded Linux PC with CODESYS, a manufacturer-independent IEC 61131-3 development environment. Liberty chose it for versatility and value: more capability in one box, a better cost point, and the ability to add functions later through development rather than more software licensing. That flexibility paid off a few months later. **Wrote the machine software.** Liberty programmed the press cycle logic. It monitors insertion depth and force on each component, compares the results to the customer's setpoints, and makes a pass/fail decision on every press-fit. The machine validates the assembly while it assembles it. Because force reflects the fit, each press also indirectly checks the upstream machining. **Kept the operator cycle simple.** A conveyor delivers the casting. The operator loads it and starts the cycle. About 10 seconds later, a finished, validated assembly comes out and goes onto the outbound conveyor, ready to ship. **Verified before startup.** Because this was new equipment, every I/O point, every function, and every calibration was checked before production began. Startup took about one week. Liberty then stayed on for roughly half a week of production support, until the customer's team was comfortable running the machine. ## **The breaking point** The machine did what it was designed to do. When a press-fit fell outside the force window, it rejected the part. In early production, rejects were sometimes treated as a machine problem rather than a process signal. As originally designed, the machine flagged a failed part and left the next step to the operator, which is typical for this kind of station. Because a part with low press force can look perfectly fine, rejects were often judged visually, and some that looked good were placed on the outbound line instead of being traced back to bore size from upstream machining. That's a common pattern when new validation equipment comes onto a floor: when the part looks right, the instinct is to doubt the machine, not the incoming part. The outcome was the one every automotive supplier works to avoid. Nonconforming parts reached the OEM. More than once, entire batches were sent back for the supplier to sort, which meant opening, inspecting, and repacking every part. Under typical automotive supplier quality terms, that containment and sort cost belongs to the supplier [\[1\]](https://www.pistonautomotive.com/wp-content/uploads/2024/04/Supplier-Quality-Logistics-and-Materials-Manual.pdf). The repeat escapes put a newly launched program at risk, one the customer had just invested in equipment and capacity to support. The press force data was there all along. What the process lacked was a way to make sure a rejected part couldn't move forward without the right people taking ownership of it. ## **The fix: a quality package that takes disposition off the station** About four to six months after the original startup, the customer engaged Liberty to close that gap. The [quality](https://www.liberty-automation.com/quality-control-data-collection-systems) package added two things. **A complete production record.** The machine had always captured press force and depth data on every part. The quality package began recording that data, pass or fail, to the customer's own quality database. **A physical quality lock.** When a part fails, the machine keeps it clamped and automatically emails the quality department a unique password. A quality team member has to come to the station and enter that password to release the part. From there, quality controls disposition, whether rework or scrap, with the failure data in hand. Rejected parts no longer depend on judgment at the station. The disposition decision now belongs to the department responsible for it. **This is where the platform decision paid off.** The lock-out logic, the database logging, and the automated quality notification were all built within the existing CODESYS and Linux system, with no added software licensing. The cost was development time, which the customer would have paid on any platform. On a traditional proprietary PLC platform, the additional software needed to support these functions could have added substantial cost. Development took about one week. Installation took two to three days and was done while the line kept running, without a production shutdown. After a few follow-up visits to review the data and make minor adjustments, the system has run in the background since. ## **The results** **One operation instead of three.** Traditionally, a part like this would move through separate press operations for each pin and bushing. The final machine presses and validates all three in a single cycle, cutting the handling and labor that a multi-step process would require. **Steady, predictable output.** The press cycle runs faster than the line requires. The line itself runs at about two parts per minute, with every press-fit validated in real time. **Rejects stay contained.** With the quality lock in place, a failed part can't move down the line until quality has it. **Data the customer can put in front of the OEM.** When the OEM asks for data, the customer can show press-force results for every part. The same data helps steer upstream machining toward nominal, so problems get corrected at the source instead of sorted out after shipment. **A program built on sound economics.** Consolidating the assembly into one validated cycle helped make the economics of the new program work, and gave the customer a new production revenue stream. ## **Why it matters** The machine never stopped measuring correctly. The weak point was what happened after a reject. When disposition depends on judgment at the station, an interference fit that looks right can still reach the customer. The more durable fix is to build that discipline into the control system itself: log every result, hold every reject, and route the decision to the people accountable for it. The project also shows the value of right-sizing. Starting from a machine built for many scenarios, Liberty and the fabrication team engineered one built for this program. It was simpler, less costly, and focused on what actually decides part quality. Platform choices made at the start shape what's affordable later. Because the controls were built on a flexible platform, the quality package was a development project, not a licensing problem. And for machine builders and fabricators: a shop with strong mechanical and panel capability doesn't need to hand a project to a large integrator to get serious controls engineering behind it. [The right controls partner](https://www.liberty-automation.com/partner-with-us) can work inside the team that's already there. **If you have a new program to quote, a machine to build, or a quality problem to solve, start a conversation.** Whether you're quoting a new production program, [building custom equipment](https://www.liberty-automation.com/custom-equipment) for a customer, or running a machine whose rejects you can't fully explain, Liberty Automation can help. Liberty provides control system specification, machine software, and in-process validation and quality logic for manufacturers and machine builders. We always start by defining what the application actually requires, then engineer the controls around it. You work directly with the principal engineer who does the work. The person defining your controls is the person who'll be standing next to the machine at startup. ### Building a machine that has to prove every part? 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