Post Processing a Part

After a part is printed, there are steps that must be followed before it can be considered ready for use or ready for other advanced processes like painting or dyeing. Following these steps will ensure a successful and usable part. This document is intended to provide general guidelines for post processing of UV curable acrylate parts for all 3D Systems MultiJet products including the ProJet® MJP 2500, ProJet® MJP 3600 and ProJet® MJP 5600 lines of printers.

Supplies Needed

Protective Clothing (lab coat, protective sleeves)
Nitrile Gloves
Insulating Gloves
Safety Glasses
Putty Knife
Paper Towels / Absorbent Pads
Mineral Oil or EZ Rinse-C
Isopropyl Alcohol (IPA)
Source for Warm Water (container or running water)
Metal Basket(s) (optional)
Plastic Bristle Brush - like a toothbrush (optional)

Equipment and Tools Needed

Freezer
Melting oven capable of heating to 65°C (149°F) such as ProJet® Finisher or ProJet® XL Finisher
MJP EasyClean System
Ultrasonic Cleaner (optional)

Steps for Post Processing a Part

Remove Parts from the Build Plate

After job is finished printing, remove the build plate with the parts attached from the printer. Lift the entire platform out the printer.

Build plate with completed parts ready for post processing

NOTE: Wear proper protective lab clothing.

NOTE: Nitrile gloves are recommended when handling parts and/or when working with fluids.

Place the platform of parts in a freezer. This will cool the parts and enables the parts to separate easily from the build plate. This can take as little as a few minutes, but may take longer for some geometries.

NOTE: Placing the print platform on a metal surface as shown here speeds up the cooling time.

Build plate with parts attached placed on a metal plate in a freezer

Once the plate is cooled sufficiently, the parts can be removed. Most parts should separate freely from the plate with the remainder easily removed with little force, leaving behind very little support residue.

Parts typically fall free from the build plate after freezing

For some geometries, it may be necessary to use a putty knife to loosen the parts. Use a plastic mallet, wood block, or small hammer to gently tap the base of each part using the putty knife until it comes free from the plate. Keep the angle of putty knife below about 30 degrees to avoid gouging or scraping the build plate.

Eye protection is required when performing this step.

If needed, lightly tap the base of the part with a putty knife

Allow parts to come to room temperature before adding to support removal heat source.

	NOTE: The putty knife can also be used to remove some parts quickly even without using the freezer.
	NOTE: Take extra care when removing very small parts or parts with fine features.
	NOTE: Take care not to scratch, groove, dent, or damage the parts or the platform in the removal process.

Bulk Support Removal from Part

Once parts have been removed from the build plate, the support material needs to be remove from the parts. This can be done in a convection oven (like the ProJet® Finisher) or using the MJP EasyClean System. These two heating systems serve similar purposes, but each has unique capabilities depending on customer needs.


ProJet® EasyClean Steamer System	ProJet® Finisher Oven
Fast Optimized for ProJet® MJP 2500 part sizes Compact and Economical, general-purpose solution Combined bulk and fine support removal	Large physical volume available High part volume "batch processing" capability Best for processing Elastomeric and Engineering Families of materials

The bulk wax is easily removed with a hands-free process. Place the parts in the Oven or EasyClean Bulk Wax Chamber. It is often advantageous to use a metal basket (accompanies EasyClean System) when processing the parts.


Metal baskets used to carry multiple MJP parts during post processing

The parts must be placed over a drip tray that will collect the melted support as it comes off the parts. This setup is included as part of the ProJet® EasyClean System. Support collection trays must also be used with an oven setup. The actual melt time will depend on the size of the part and how much support wax is present. The ProJet® EasyClean System operates similar to a vegetable steamer and runs at 100°C. The oven should be set to 65°C (149°F). For best part quality, remove the parts as soon as the bulk wax material has melted off all the parts from either system. For some parts, this can take 30 minutes or longer. The ProJet®EasyClean System is much faster compared to the ProJet® Finisher Oven.

	NOTE: Do not let the parts soak in the molten support wax in the oven.
	NOTE: For best quality, avoid stacking parts on top of one another.


ProJet® Finisher oven or larger convection oven

Remove parts from oven and wipe off any remaining support material with a paper towel. Alternatively, one can place the parts for a few minutes on an absorbent paper towel while heated in the oven or ProJet® EasyClean System.

Wipe off any remaining support material with a paper towel

Caution: Be careful when handling hot parts and always wear gloves.

Fine Wax Removal from Part

The remaining support wax on the part is easily dissolved away with a hands-free process. Either the EasyClean System or an ultrasonic bath can be used. These two systems serve similar purposes, but each have unique capabilities depending on customer needs.


ProJet® EasyClean Steamer System for fine wax removal	Ultrasonic Bath for fine wax removal
Fast Economic, general purpose solution Combined bulk and fine support removal solution Optimized for ProJet® MJP 2500/3600 size	Large physical size is available Removes support better on the finest of features Best for entrapped support removal which may require longer processing times Best for processing Elastomeric and Engineering Families of materials

The EasyClean System is an economic general-purpose solution for most customer needs. A heated ultrasonic bath is better for very small features. It is also synergistic with the removal of support that is entrapped in very fine features within a part (like internal flow visualization channels or when the support is present within the part to create a light composite structure). The action of the ultrasonic bath removes the support more quickly and is more effective. The EasyClean System is also fixed in physical size. Ultrasonic baths can be purchased for large part size needs. Both systems work for all materials.
Either EZ Rinse-C or light mineral oil can be used for the fine wax removal step in either the EasyClean System or the ultrasonic bath. These two fluids serve similar purposes, but each has unique capabilities depending on customer needs.


Two convenient materials for MJP fine wax removal step to serve your part needs
Easily rinses away with water Dissolves support wax quickly	Requires liquid dishwashing soap (Dawn) to remove oil Best for processing Elastomeric and Engineering Families of materials Best long term part aesthetic (long term injection molded plastic look and feel) Best for entrapped support removal which may require longer processing times.

CAUTION: Use gloves to avoid contact with the solvents.

For both fine wax removal solvents, the parts are placed directly in the liquid that is held at approximately 65°C (149°F). Leave the parts in the liquid until the wax is removed. Keep the time in the EZ Rinse-C or Mineral Oil as short as possible (2-5 minutes). If using the EasyClean system (which has no agitation), a gentle swirling of the part in the chamber can aide in removing the residual wax. The ultrasonic action is very efficient in removing residual wax with no additional manual agitation required. For certain parts, like complex parts or parts with entrapped cavities, it may be necessary to leave the parts in the mineral oil bath for more time.


Parts placed in either EasyClean fine wax removal system or into the ultrasonic bath

NOTE: EZ Rinse can be purchased from your printer sales team

NOTE: White mineral oil – light viscosity should be sourced locally in your country of origin.

McMaster: https://www.mcmaster.com/#mineral-oil/=19o67sv

W.S Dodge Oil, 3710 Fruitland Ave., Maywood, Ca 90270, (323) 583-3478, www.wsdodgeoil.com

Hardware stores or grocery stores typically carry mineral oil

Rinse parts with warm soapy water. The best practice is to use a fresh tub of hot soapy water. When using mineral oil use extra soap in the water. It is acceptable to apply the soap directly on the part and use a light brush (such as a toothbrush) to clean the part.


Fresh tube of soapy hot water with light brushing of part if needed

Wipe parts dry with a paper towel or absorbent pad or allow them to air dry. Clean, dry compressed air blown lightly over the parts can be used to speed the drying time.