In 2026, AMD Machines quoted a two-position bubble leak test station for an automotive supplier that casts aluminum housings at a US plant. This case study walks through that quote: what was in the machine, what it cost in round numbers, why the design looks the way it does, and what the buyer is responsible for. The customer isn't named, and prices are shown as ranges. Everything else comes from the quote and from the engineering discussion behind it.
It's a quote, not a delivered machine. We're publishing it because buyers rarely see what a bubble tester actually costs. For the full range of leak and functional testing we build, see our automated test systems page.
A bubble leak test station is a machine that seals a part's openings, pressurizes it with air and holds it under water, so an operator can watch for the stream of bubbles that marks a leak and its exact location. The station AMD Machines quoted here did that for two housing models in two independent test rigs.
What Is in This Bubble Leak Test Station?
The machine is built around a welded steel frame with a stainless steel water tank. Two testing rigs, Testing Rig 1 and Testing Rig 2, share that frame, the tank, the controls and the operator interface, but each rig has its own fixture, clamps, seals, pressure sensor and lowering mechanism. One operator loads and unloads both. AMD Machines specified the equipment by brand in the quote:
| System | What AMD Machines quoted |
|---|---|
| Structure | Welded steel profile frame with base plate; welded stainless steel water tank with a water level sensor |
| Part handling | One hinged lowering mechanism per rig, driven by an SMC pneumatic actuator, with position sensors |
| Clamping | Six Destaco pneumatic clamps per rig, with mechanical locking so a part can't drop if air pressure is lost |
| Sealing | A polyurethane sealing plate on the main face of each housing, plus two FasTest pneumatic seals per rig for the shaft outlet openings, each pair driven by SMC actuators |
| Pressure | One pressure sensor per rig to confirm the part reached test pressure before it goes under water; two manual regulators to set test pressure |
| Pneumatics | SMC filter-regulator-lubricator unit, seven SMC valves and related SMC components |
| Controls | Siemens S7-1200 1214C PLC with a Siemens I/O module, SIMATIC HMI MTP700 Unified Basic operator panel, Rittal control and HMI enclosures, Ethernet |
| Safety | Two Sick safety light curtains, two Optotouch cycle-start buttons, a Euchner interlock, two Allen-Bradley emergency stops, Euchner safety relay with Omron force-guided relays |
| Lighting | Two status lights and an area light for loading, unloading and the visual inspection |
The design basis in the AMD Machines quote: two housing models at 150,000 parts each, 300,000 parts a year combined, a 110-second cycle per part, one operator for loading and unloading, 440 V supply and 24 V controls.
How Much Does a Bubble Leak Test Station Cost?
The station AMD Machines quoted came to between $110,000 and $130,000 installed at the customer's US plant. The quote priced it in five lines, shown here as ranges:
| Line | Price range |
|---|---|
| Base machine with two test areas: frame, stainless tank, controls, HMI, safety | $55,000–$65,000 |
| Testing Rig 1: fixture, clamps, seals, pressure sensor, lowering mechanism | $20,000–$25,000 |
| Testing Rig 2: same scope | $20,000–$25,000 |
| Shipping and insurance to a US facility | $5,000–$7,500 |
| Installation and commissioning: two engineers on site for four days, travel included | $5,000–$7,500 |
| Total installed | $110,000–$130,000 |
That total sits in the lower half of the $75,000–$250,000 range AMD Machines publishes for a typical single-station automated test system. Sales tax was excluded. Payment was 40% with the purchase order, 35% at design release, 15% at approval in AMD's facility and 10% at final approval in the customer's plant, with a 12-month warranty.
Three things move the price of a bubble tester more than anything else:
- How many rigs. Each rig in the AMD Machines quote cost roughly 20% of the installed total. A single-rig version costs less but tests one part at a time.
- How hard the part is to seal. Fixtures, clamps and custom seals are where a large, complex casting costs money (next section).
- Who makes the leak call. This station leaves the pass/fail decision to the operator. Adding automatic bubble detection, or switching to an instrument-based method, changes the machine and its price.
For budget ranges across other kinds of automation, see our guide to what automation costs.
Why Does Sealing Drive the Design of a Bubble Leak Tester?
Every square inch of sealed area pushes back with the full test pressure. At 2 bar (29 psi), the figure AMD Machines' engineers used to size this machine, each square inch of sealed face needs 29 lb of clamping force just to hold the seal shut. A housing face of 100 square inches would need about 2,900 lb before any safety margin. The housings in this quote had a very large sealing surface, which is why the first note from AMD's engineering team was about clamps, not tanks: the machine would need heavy ones.
That's where the six Destaco clamps per rig come from, and why the quote specified clamps with mechanical locking. If plant air drops while a pressurized housing hangs over a water tank, a self-locking clamp keeps it in place. The main face seals against a polyurethane plate, and the two shaft outlet openings are closed with FasTest pneumatic seals.
If you're scoping your own tester, measure the largest sealed area before anything else. It sets clamp size, frame stiffness and a good part of the price.
Why Check Pressure Before the Part Goes Under Water?
A part that isn't sealed properly will bubble whether it leaks or not, and the operator can't tell a bad seal from a bad casting. So the AMD Machines design adds a gate: after clamping and sealing, the rig pressurizes the housing, and the pressure sensor must confirm it reached test pressure before the hinge lowers it into the tank. If pressure doesn't come up, the cycle stops and the HMI tells the operator, usually because the part isn't seated or a seal isn't closed.
A second gate checks the tank. A water level sensor blocks the cycle if the water is low, because a housing that isn't fully submerged can't be inspected fully.
The quote was explicit about what the pressure sensors are not: they confirm the part is sealed and pressurized, and they don't perform a pressure decay leak test unless that's specified separately.
How Does the Test Cycle Run?
The quote described the cycle step by step:
- The operator loads a housing into one rig.
- The machine checks the tank water level.
- The operator starts the cycle with that rig's Optotouch button.
- The Destaco clamps close on the part.
- The seals close the shaft outlet openings.
- The part is pressurized to the test pressure.
- The pressure sensor confirms the part reached that pressure.
- If it did, the hinge lowers the part until it's fully under water; if not, the cycle stops and alerts the operator.
- A stabilization period runs while the part stays pressurized.
- A green light tells the operator the inspection window has started.
- The operator watches the part for bubbles.
- Pressure is released, the part rises out of the tank and the operator unloads it.
Test pressure, the pressure validation limits, the stabilization time and the inspection time are all set on the HMI. Because the two rigs run independently, the operator loads one while the other is under water.
Bubble Test, Pressure Decay or Mass Flow: Which Should You Buy?
A bubble test shows where a part leaks. Pressure decay and mass flow tell you how much it leaks, as a number. That's the whole trade-off:
| Bubble (immersion) test | Pressure decay or mass flow | |
|---|---|---|
| What the result is | An operator sees bubbles, or doesn't | An instrument reads a leak rate against a limit |
| Finds the leak location | Yes, you see exactly where it is | No, it only says the part leaks |
| Pass/fail decision | Operator judgment during an inspection window | Automatic, with data for traceability |
| Typical use | Porosity hunting on castings, diagnosis, repair and rework | 100% production testing to a stated leak specification |
| Sensitivity | Depends on pressure, inspection time and the operator | See our comparison of leak testing methods |
This AMD Machines quote was a visual bubble test by design: the clarifications stated that the machine wouldn't make an OK/NOK call on its own. That's the right machine when someone downstream asks for a bubble test, or when you need to see where a casting leaks. When the specification is a leak rate, an instrument-based automated leak test station is the better buy.
The test method on a part is usually written into the end customer's specification, and specifications can change late, so confirming the test method and leak limit with your customer early protects the investment in any leak tester.
What Safety Does a Bubble Leak Tester Need?
The operator works at the tank, next to heavy clamps and parts that swing down into water. The AMD Machines quote guarded each rig with a Sick safety light curtain and required the operator to start each rig's cycle from its own Optotouch button, outside the light curtain. A Euchner interlock, two Allen-Bradley emergency stops and a Euchner safety relay with Omron force-guided relays complete the safety circuit, and the self-locking clamps hold the part if air pressure is lost.
The quote also included a first draft of an ISO 12100 risk assessment before the factory acceptance test. For a US plant, it's worth stating in your request for quote that you want the control panel built to UL 508A and the machine to NFPA 79, so that's priced in from the start.
What Does the Quote Include and Leave Out?
The AMD Machines quote included the machine, shipping with insurance to the customer's US facility (delivered DAP), and two engineers on site for four days to install and commission it. The documentation package listed:
- full 3D and 2D files in STEP or SolidWorks format, delivered about two weeks after the machine to include final debug changes
- operator's manual, troubleshooting guide and technician's manual
- the ISO 12100 risk assessment, equipment specifications and installation guide
- electrical and pneumatic diagrams, a preventive maintenance plan, a spare parts list and the full bill of materials
The buyer is responsible for:
- offloading the crates on arrival
- site preparation and floor loading
- bringing electrical, pneumatic, network and exhaust utilities to the machine's connection points
- confirming in writing that the machine sat in its final position
- sales tax
How Long Does It Take to Build a Bubble Leak Test Station?
AMD Machines quoted 16 weeks from purchase order to the machine being ready for its factory acceptance test at AMD's facility in Querétaro, Mexico. Shipping and the four-day installation follow. The work runs through AMD's eight execution stages: commercial start, kickoff, design, manufacturing and factory validation, shipment preparation, installation, handover with a site acceptance test, and closure.
For comparison, AMD Machines delivers simple machines in as little as 6 weeks and complex systems in 24–26 weeks, against 40–42 weeks typical for overseas builders. A two-rig manual-load tester lands between the two. See our custom automation lead times for what sets the schedule.
What Should You Send to Get a Leak Tester Quoted?
AMD Machines quotes a leak tester from your part and your specification. Send:
- 3D models of every part model to be tested, with the openings that must be sealed marked
- the test method and leak limit your customer requires, or the test pressure if it's a bubble test
- annual volume per model, shifts and your target cycle time
- how many operators you plan, and whether the station stands alone or sits in a line
- your plant voltage and preferred brands for PLC, HMI, pneumatics and safety
- sample parts: the standard terms ask for 50 of each model with the purchase order, for tuning and the factory acceptance test
Bubble Leak Test Station FAQ
How much does a bubble leak test station cost?
The two-rig station AMD Machines quoted in 2026 came to $110,000–$130,000 installed in the US, including shipping and four days of commissioning. Each of its two test rigs was priced at roughly $20,000–$25,000 on top of a $55,000–$65,000 base machine. Automatic bubble detection would add to that.
What pressure is used for a bubble leak test?
It's set by the part's specification. This AMD Machines station set test pressure with manual regulators, and its clamps were sized for 2 bar (29 psi). At that pressure every square inch of sealed area needs 29 lb of clamping force.
Can bubble detection be automated?
Yes, with cameras or ultrasonic sensing that detect bubbles leaving the part. AMD Machines has run preliminary tests of ultrasonic bubble detection but hasn't yet built it into a production system. When a line needs an automatic pass/fail result, pressure decay or mass flow testing is the standard route.
Is bubble testing accurate enough for production?
For finding where a casting leaks, bubble testing is hard to beat: you see the leak. For proving every part meets a leak rate, use an instrument. A common setup uses both: an instrument-based tester on the line, and a bubble tank to find where the rejected parts leak.
If you're budgeting a leak tester, send us your part and specification and AMD Machines will tell you which method fits and what it costs.