Why the base interface decides robot life

The foundation plate and leveling system transfer every dynamic load from the robot into the floor. A poorly specified base shows up later as vibration, positional drift, premature gearbox wear, and failed repeatability tests. For buyers sourcing base plates and leveling hardware from Chinese fabricators, the goal is to lock down geometry, material, and flatness before the quote—not after the first article inspection.

Foundation plate types and when to use each

• Welded steel base plates: The default for floor-mounted industrial arms. Fabricated from structural steel, machined on the top face for the robot mounting pattern. Best for medium-to-heavy payloads and where the plate is embedded or anchor-bolted to a concrete slab.
• Cast iron base plates: Higher damping and stiffness per unit weight. Specify when vibration transmission is a concern or when the plate doubles as a precision datum. Expect longer lead times and higher per-kg cost.
• Modular/adapter plates: Machined plates that adapt a robot's bolt pattern to an existing foundation or to a linear track. Common in retrofits and integrator builds where the floor cannot be modified.
• Leveling wedges and shim packs: Used between the plate and floor or between plate and robot. Wedges allow field adjustment; shims are cheaper but require trial-and-error fitting.

What to specify before ordering

Chinese fabricators will build to your drawing, but ambiguous drawings invite rework. Put these on the RFQ:

• Mounting pattern: Bolt circle or hole pattern, thread size and pitch, hole tolerance (e.g., H7 for dowel locations), and whether holes are through or blind.
• Flatness and parallelism: State flatness of the robot mounting face and parallelism to the floor interface. Typical industrial requirements are 0.1–0.2 mm/m; precision applications need tighter. Specify the measurement method (surface plate, laser, or CMM).
• Material and grade: Name the steel grade (e.g., Q235B, Q345B, or equivalent S355) or cast iron grade. Ask for mill certificates.
• Surface treatment: Machined faces are usually left bare or lightly oiled; non-machined surfaces get primer or powder coat. Specify coating thickness so it does not interfere with datum faces.
• Anchor and leveling interfaces: Anchor bolt hole diameter and spacing, leveling screw threads, and access for grout. If the plate is grouted, specify grout holes and vent holes.
• Lifting and handling: Lifting lugs or tapped holes for eye bolts on plates over ~100 kg.

Leveling methods and hardware

Leveling is where most installation errors occur. Decide the method at the design stage:

• Leveling wedges: Stackable steel wedges under the plate. Fast to adjust, but they can creep under vibration; lock them with welds or locking plates.
• Leveling screws/jacks: Threaded adjusters through the plate. Good for heavy plates; require a locking nut and a grout pocket underneath.
• Shim packs: Stainless or brass shims in fixed increments. Cheapest and most stable once set, but slow to install.
• Epoxy grouting: After leveling, grout the gap to distribute load and damp vibration. Specify grout strength and cure time; ensure the plate has grout holes.

Whichever method you choose, require the fabricator to match leveling hardware to the plate—thread sizes, wedge angles, and load ratings—so you are not mixing suppliers at the site.

Cost considerations

Base plate cost is driven by mass, machining time, and inspection level, not by the raw steel price alone.

• Machining: A single large machined face is cheaper than multiple tight-tolerance features. Consolidate datums where possible.
• Flatness tolerance: Tightening from 0.2 mm/m to 0.05 mm/m can add 20–40% to machining cost because it requires stress relief and additional setups.
• Stress relief: Welded plates should be stress-relieved before final machining. Ask whether this is included; skipping it risks distortion after installation.
• Inspection: Third-party inspection (e.g., SGS, TÜV) adds cost but is worth it for critical bases. Specify whether inspection reports are required per unit or per lot.
• Volume: Chinese fabricators typically quote lower per-unit for batches of 5–10 plates; single-piece orders carry setup cost.

Sourcing tips for Chinese fabricators

• Send a fully dimensioned drawing, not a sketch. Include GD&T for flatness and parallelism, material grade, and surface treatment. Chinese machining shops are capable but will not guess your intent.
• Ask for a first article inspection (FAI) report with actual measurements, not just a certificate of conformance.
• Clarify Incoterms and packaging. Machined faces need protection—specify wooden crates with rust-preventive wrap and face protection.
• Check export experience. Fabricators who regularly ship to Europe or North America understand packaging and documentation requirements.
• Request stress-relief records for welded plates; this is a common omission that causes field problems.

Bottom line

Specify the foundation plate like a precision component, not a steel fabrication: define flatness, material grade, mounting tolerances, and leveling interface on the drawing, require stress relief and FAI reports, and match leveling hardware to the plate at the sourcing stage. Done right, the base is a one-time cost that protects the robot's accuracy for its entire service life.