1. Key Challenges of Fastener Cleaning
Fasteners include bolts, nuts, washers, high‑strength alloy‑steel screws and stainless‑steel fasteners. Thread crevices are narrow and deep, which brings difficulties to conventional cleaning methods.
Types of contaminants: cold‑heading oil, cutting oil, quenching oil from heat treatment, polishing wax, iron dust, pickling residues, passivation remnants and hand‑induced grease.
Core difficulties: dirt is trapped deep inside thread gaps and cannot be fully removed by simple soaking. Cleaning 10.9‑12.9 grade high‑strength steel with improper methods will lead to hydrogen embrittlement. Water stains easily form on stainless‑steel parts after washing. Mass‑production requires consistent cleanliness and thorough drying. Automotive fasteners need to meet OEM particle‑cleanliness standards.
Two mainstream solutions developed by Sinobakr: water‑based ultrasonic cleaning and vacuum hydrocarbon / modified‑alcohol enclosed cleaning.
2. Solution 1: Multi‑Tank Water‑Based Ultrasonic Cleaning Solution (Cost‑Effective for Mass‑Produced Carbon‑Steel and Stainless‑Steel Standard Parts)
2.1 Equipment Configuration: Sinobakr Fully‑Automatic Basket‑Rolling Cleaning Line
Components: loading basket → main ultrasonic washing tank → primary spray rinsing → DI‑water secondary rinsing → hot‑air drying → unloading. The tank body is made of 304 / 316 stainless‑steel with adjustable ultrasonic power. Rolling baskets rotate 360° to turn over workpieces. The PLC‑controlled system is equipped with circulating‑filtration and oil‑separation modules.
2.2 Standard Process Flow
Pre‑cleaning tank: Apply weakly‑alkali Sinobakr‑specialized water‑based fastener detergent at 50‑60 °C with ultrasonic waves and rolling for 10‑15 minutes to strip quenching oil, cold‑heading oil and iron powder. Low‑hydrogen detergents are selected for alloy‑steel parts to avoid hydrogen‑embrittlement risks, while neutral detergents are adopted for stainless‑steel components to prevent surface darkening.
Primary spray rinsing: High‑pressure flowing tap‑water washes off most grease and residual detergent.
Secondary DI‑water ultrasonic rinsing: De‑ionized‑water ultrasonic rinsing eliminates chemical residues to prevent subsequent rusting and water‑mark formation.
Hot‑air & vacuum drying: Dehydration at 80‑120 °C with negative‑pressure circulation ensures no trapped moisture inside threads. A continuous water‑break‑free film is achieved to meet pre‑plating and phosphating requirements.
2.3 Application Scope and Advantages
Suitable for carbon‑steel and stainless‑steel fasteners before galvanizing, hundreds‑of‑thousands‑piece daily‑output mass‑production of standard‑parts.
Benefits: moderate equipment investment and low detergent cost, VOC‑compliant eco‑friendly formula and consistent cleaning performance.
