Proses Pretreatment adalah proses pengkondisian awal dari permukaan logam dilapisi ( coating ) dengan senyawa logam agar lebih tahan karat sebelum di proses pengecatan. proses Pretreatment diperlukan karena akan meningkatkan ketahanan terhadap karat dan meningkatkan daya rekat cat terhadap permukaan benda kerja.

Proses Pretreatment ada beberapa type yang dipilih tergantung untuk material yang benda kerja tersebut dan standard ketahanan terhadap karat yang diinginkan. Beberapa tipe Pretreatment sebagai berikut :

1. Coating untuk Besi dan turunannya

• coating type Fe ( iron phosphate )
• coating type Zn ( Zink Phosphate )
• Coating type mn ( manganize Phosphate )

2. Coating untuk Aluminium

• Coating Cr6+
• Coating Cr3+
• Coating Ti
• Coating Zr

Bentuk Proses Pretreatment bisa 2 jenis, yaitu dengan proses Dipping / Celup atau dengan proses Spray.
Tahapan Proses Pretreatment

Degreasing - Air Bilas - Surface Conditioning - Coating - Air Bilas - Air Bilas

Fungsi tahapan Proses

• Degreasing --> menghilangkan minyak, lemak dan polutan diatas permukaan material
• Air Bilas --> membersihkan permukaan material dari proses sebelumnya
• Surface Conditioning --> menunjang proses terbentuknya kristal coating
• coating --> membentuk lapisan coating senyawa logam di permukaan material untuk meningkatkan daya tahan karat dan kerekatan cat

Pretreatment process is the initial conditioning process of metal surface coated with metal compound to be more rust resistant before painting process.

Pretreatment process is necessary because it will increase the resistance to rust and increase the adhesion of paint to the workpiece surface. Type of Pretreatment

1. Coating for Iron and its derivatives

• coating type Fe ( iron phosphate )
• coating type Zn ( Zink Phosphate )
• Coating type mn ( manganize Phosphate )

2. Coating for Aluminum

• Coating Cr6+
• Coating Cr3+
• Coating Ti
• Coating Zr

Pretreatment process form can be 2 types, namely by Dipping / Dip process or Spray process.
Stages of Pretreatment Process

Degreasing - Rinse - Surface Conditioning - Coating - Rinse - Rinse

Process stages function

• Degreasing --> remove oils, fats and pollutants on the surface of the material
• Air Bilas --> clean the surface of the material from the previous process
• Surface Conditioning --> supporting the process of crystalline coating formation
• coating --> forming a layer of metal compound coating on the material surface to enhance the rust resistance and paint density