Investment Casting VS Sand Casting – What’s the Difference

Investment casting and sand casting are both included in the casting manufacturing method and have a long history that can date back to 1838. Though both of the two casting methods are making metal parts by pouring the molten metal into a mold, there are significant differences between them. This article will explain all the differences between them. In only 5 minutes, you will find the right choice for your casting manufacturing with the basic information of them.

What is investment casting?

Investment casting manufacturers create a wax pattern to create the void for producing metal parts. The ceramic shell was built around the wax patter, and when it was hard enough, manufacturers will remove the wax pattern inside from the shell. Then pour the molten metal into the shell, allowing it to solidify. Final investment casting parts will have a smooth surface and the same shape as the wax pattern. Besides, the removed wax can be reused next time.

What is sand casting?

Sand casting compacts sand around a pattern of a model of the final product. to create a sand mold. Most of the time, manufacturers mix the sand with clay and moistened it with water to make the mold tough. One sand mold just can use one time, while the sand can be reused. The sand mold was made by two halves, and when it is used for casting, the two halves will be fastened closely.

Investment Casting VS. Sand Casting

castinginvestment casting vs sand casting

Though both investment casting and sand casting are included in casting technology. To be precise, there are significant differences between them from the sand casting process, metal material, size, investment casting surface finish, and rough casting cost. “Investment casting vs. sand casting” is a common topic, so what is the difference between sand casting and investment casting?

Differences Between Investment Casting and Sand Casting

Let’s talk about the difference between sand casting and investment casting in detail below. The first is the process difference between them.

Generally speaking, the investment casting process has 8 main processes.

  • Creating a wax pattern
  • Wax tree assembly
  • Shell building
  • Wax removing
  • Metal pouring
  • Shell knock off
  • Cut off the parts
  • Individual casting
Liquid wax builds complex geometries, just need one reusable mold. The entire shape will be dipped when the wax is solidified and put into the liquid ceramic for a shell. Therefore the ceramic shell it made nearly included all details that the wax pattern has. And the design of the wax pattern should be according to the final products.
investment casting vs sand casting

6 main sand casting processes.

  • Create a mold pattern in the sand
  • Set up the gating system
  • Remove the mold pattern
  • Pour molten metal into mold void
  • Metal solidification
  • Remove the metal casting

The mold pattern was made before the sand casting began, and the pattern can be used in the next mold making. And the sand mold can be used at one time. When you finish the metal casting, the sand mold will be destroyed.

Metal Material

Investment Casting VS Sand Casting is also reflected in the metal materials used. Factor metal material tolerance, melting point, and other features, casting manufacturers should consider material selection when creating casting business. If you want to cast non-ferrous metals like aluminum and magnesium, the investment casting can finish the casting process. It also has its suitable casting alloy for sand casting, though there may be some materials that the investment casting can also make.

There is a list of casting material selections:

Sand casting: iron, steel, bronze, brass, aluminum, magnesium, and other non-ferrous alloys.
Investment casting: stainless-steel alloys, brass, aluminum, carbon tell.
Investment Casting VS. Sand Casting Size and Weight
Generally speaking, the metal parts that Investment Casting VS. Sand Casting made differ in size and weight.

Investment casting: It has a wax pattern made from mold by injecting the wax, and this kind of part allows more fine details. When the pattern dipped into a liquid ceramic for building a shell, the details have been retained as much as possible. Therefore, investment casting can be sued at more precise, complex, and small metal parts casting. There is the very little limitation of the size and weight of investment casting.
Sand casting: It needs a mold pattern to create a mold cavity. Sand casting can not often cast the small, complex metal parts as investment casting. Molding larger parts with sand casting may have a good effect.

Investment casting surface finish

Investment casting provides a smooth, investment casting surface finish for metal parts. While because of the two halves of the sand mold, the surface finish will have a seam left by the parting lines in the mold. Besides, the sand mold has a relatively rough inside, for the final casting surface finish of the metal part will have an equally rough surface.

Investment Casting VS Sand Casting Cost

Investment casting has an expensive pre-production cost to prepare a wax pattern and ceramic shell and finally make smooth finished products. While sand casting has a lower cost than investment casting, it needs an after-the-process to deal with the rough surface of the final product.

Aspects You Should Consider for Casting Manufacturing

Investment Casting VS. Sand Casting

If you want to create a casting business, choosing the right casting method is important to achieve success. There are 5 aspects you should consider for casting manufacturing.

Material

Before considering this aspect, you should think about factors. What are the most suitable materials for your products, which casting methods are better for them? Materials tolerance, melting point, and other features should be included.

Annual Volume

You should consider the payback period of casting tool cost, find the balance between the income and expense. Investment casting may have an expensive tool to spend, while sand casting has a lower cost at the casting tool.

Cycle Time

Both investment casting and sand casting can achieve mass production, while they have very different cycle times. Sand casting may need a long time to produce and other time to deal with the rough surface. In comparison, investment casting provides a quick production process and shot cycle time with no after-process products.

Cost

If the production cycle time occupies an essential part of the cost, you should consider the real cost. Investment casting has a short cycle time and has no other extra time and cost for producing. Investment casting has to create other costs and time for rough product surface dealing.

The above is about Investment Casting VS. Sand Casting. Dawang investment casting is a specified casting partner. If you want to know more about Investment Casting VS. Sand Casting, please connect with us. Leave a comment or email us, we will reply to any question as soon as possible.

How many times can a sand mold be used?

The short answer is yes, the casting sand in sand casting can be reused. Sand casting is one of the oldest manufacturing methods, and the use of sand has certain advantages over other casting methods such as plaster or die casting.

One of the biggest benefits of this method is that the casting sand can be reused. So sand casting cost is a cheaper and more efficient option for producing runs and parts. However, regeneration is usually required to ensure the best results on castings that contain previously used sand. In order to reuse wet sand, you must first separate it from the impurities left by the metal from the previous casting. Before reusing, it is important to filter out any material left over from the last casting process to ensure the best possible product. Failure to do so can lead to a variety of casting defects.

The process of regenerating and replacing cast sand is usually more expensive than the cost of the sand itself. For this reason, most manufacturers choose to recycle the sand elsewhere and purchase fresh, new sand for subsequent castings. Approximately 70% of used casting sand is recycled rather than discarded. The recovered sand may end up as part of a road or other construction project or for more technical agricultural, or geological applications.

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