Chrome Finishing For 3d Powder Prints

Transcription

1 Chrome Finishing For 3d Powder Prints

2 Powder Printing is definitely a very good technology for producing complex parts, but it can only generate the shape and that is not all about the appearance. Post processing is always recommended for powder printed parts. One such process is the Surface Finish which ranges from a general sanding to a high glossy and colorful surface. The procedure for achieving different levels of surface finish for powder printed parts is described in the following sections. This procedure is prescribed only for structurally sound parts like Solid or Hollow parts with good amount of thickness, as the parts are subjected to reasonable amount of stress during the procedure (especially during sanding). Material Required: Wet sanding papers ranging from Grade 200 to 600 or more. Wiping cloth Wet sandable primer Canister Spray Paint Canister Stand arrangement for hanging the parts

3 Step-by-Step procedure: Sand all the surfaces of the part with a 200 Grade Sand paper. This will get rid of extra powder sticking on to the surface of the parts. Make sure that you don t apply too much pressure during sanding, as the parts are still not very strong. If you think that the parts are weak, you may omit this step. Now, apply the epoxy resin coat on the surface and let it cure for at least 24 hours. Now the parts must be strong enough to be sanded. Start sanding the surfaces with different sand papers starting from 200 Grade and increasing up to 600 Grade or more. Dry sanding is recommended at this stage, as the parts are still prone to reaction with water.

4 At this stage, the part achieves a very smooth surface. If good amount of sanding is done, the surface finish is comparable to a grinded marble finish. If coloring the surfaces is a part of the plan, then prime the surfaces with a wet sandable primer. After it dries up, sand the surface delicately with wet 600 grade sand paper. Repeat this process for 2 or 3 times to achieve a smoother finish. Once the priming is completed, the part is good to be painted. Hang the part such that none of its surfaces touch any thing during the painting process. This is to avoid any stains or finger prints on the part s surface.

5 It is recommended to go for atleast 2-3 coats of spray paint to achieve a smooth and shiny surface. Finally, apply 2-3 layers of clear coat to achieve the glossy appearance. Points to remember: Surface finish is a very sensitive process and any mistake at this stage will leave unwanted stains on the surface and that kills the beauty of the parts. Hence, following points are to be remembered through out the process: Make a proper arrangement for the part to be hanged free of any contact with any external agents. It is advisable to provide provision for this in the design as demonstrated in the figure below:

6 Always get rid of residue from the surface using a wiping cloth after sanding. Avoid spraying too much paint per coat as this result in dripping of paint which spoils the edges. Though the spray paint claims to be fast drying (15 mins) it is recommended to wait for about 1 hour before handling it with hands. All the sanding after priming should be wet sanding, as the sandpaper collects a lot of residue on it and that makes the sanding surface immune to further sanding. Wetting the sandpaper will get ready of this residue and results in a uniform sanding. For efficient priming and painting, follow the instructions given on the paint canister. The key to a good surface is efficient sanding. It must be noted that all the surfaces and corners are well sanded to achieve uniform surface. Comparison of Surfaces before and after the procedure: The difference in the appearance is significantly flaunted in the above picture. The flow chart for achieving the above appearance is shown in the following figure: