fbpx
Back

Irreplaceable Parts? Replicate with Low-Cost 3D Printed Molds

MAR 18, 2018

 

Caxton3D Created 3D Printed Molds for Sand Casting

 

“I hope that there will be more interest in the future for printing for ‘real world’ tasks. Pattern making is one of the most obvious applications. Most patterns today are still hand produced from wood.”

 

In order to replace the water manifold on a 1913 Dennis Fire Engine, Raise3D Forum user Caxton3D created CAD models and molds for sand casting to create an aluminum part for an otherwise irreplaceable engine part.

With the difficulty in welding aluminum of this age, sand casting becomes the only solution for repairing this type of part. the sand casting aluminum process brings a number of variables that must be considered, such as the contraction of metal parts during cooling and core molds for hollow castings. To properly achieve the final results, the Raise3D N2 Plus is used 3D printed molds as an integral part of this skilled casting process.

 

Metal Sand Casted Manifold with 3D Printed Prototype

Casted water manifold on a 1913 Dennis Fire Engine and 3D printed prototype model.

 

3D Printing Saves Cost in Sand Casting

 

Without the aid of templates or factory drawings, the casting of replacement parts required a high level of trial and error with handmade wooden models. With the aid of 3D printing, digital models can be easily adjusted and used to create low-cost, 3D printed prototypes and negative mold models.

 

Before including 3D printing, the industry’s traditional methods consisted of:
1. Labor intensive hand-carved wood models for impressions
2. Varying inaccuracies due to hand-made parts
3. Multiple castings to create positive and negative models

 

By 3D printing molds for casting, the process has:
1. Reduced costs with prototyping and test models
2. Reduced labor with automated printing processes
3. Increased accuracy with precision digital models

 

Company: Raise3D forum user Caxton3D
Industry​ ​or​ ​Trade: Aluminum Sand Casting
Raise3D​ ​system​ ​being​ ​used: Raise3D N2 Plus

3D Printing Molds for Casting

 

Process:
To begin a cast, Caxton3d first creates a digital replica of the manifold using Solidworks.
For parts of this age, factory drawings are not readily available, so dimensions are taken from the original piece and translated into a CAD model. This design is printed as a prototype and installed onto the original hardware to measure fit and tolerances. Taking into consideration the amount of shrinkage that the metal will experience with cooling, the necessary changes are made in the model until the desired outcome is met.

 

CAD modeled manifold

Solidworks model replicated with gathered measurements.

 

3D printed manifold prototype attached to the cylinder head for fit testing

3D printed prototype attached to the cylinder head for fit testing.

 

Now that the manifold has been designed, Caxton3D will use the model to create a positive and a negative to create the mold.

This modified model is designed with both the manifold face and the core. A ‘core’ is added which will be used to prevent metal from flowing, creating a hollowed part.  The extrusions from the core will be used to rest the separately-molded sand core within the mold.

 

Modified model with positive manifold half and core in the CAD software

The modified model with positive manifold half and core.

 

Inside Raise3D printer, a completed 3D print of a positive mold model.

Completed print of a positive mold model.

 

To create the sand core, a negative of the model is printed as a two-part mold. When creating a part like this, which is much larger than the bed of the printer, each half will be split into two parts and joined together to create the mirrored halves. To ensure alignment Caxton3D added registration marks for bolts that will create a continuous core box.

 

1/2 of the sand core mold.

 

Sliced model of the core mold. Each half will be printed in 2 parts to allow printable size.

 

To complete the cast, the modified positive is used to create the initial impression into the sand. This will be made in two halves. One of these two halves will be given a trough for metal to be poured in to.
The molded sand core that is removed from the two-part mold will be enclosed within the two sand halves. Metal is poured, and the final aluminum piece is removed.

 

The 3D model with part (silver) and core mold (Black). Cross-section of sand mold and sand core (red). Final aluminum casts.

 

Final aluminum sand cast manifold attached to the cylinder head

 

Learn more about how Raise3D can influence your industry

Contact Our Experts:
1-888-963-9028

Do you have a great 3D printing success story and think it would be cool to be featured on this blog series? We would love to learn more! Write to us at inquiry@raise3d.com

For more information about Raise 3D printers and other services, check us out at our website: Raise3D.com or schedule a demo with one of our 3D printing experts.