Markforged for Investment Casting

The Markforged X3 is our “pattern producing machine”, we have customers that are saving 10’s of thousands per casting. We are literally changing the way investment casting, a 100+ year old industry, operates.

What a Foundry Prints

Markforged customers have seen huge impacts in printing patterns for the match plate sand casting process (Explore Sand casting at the bottom of this post). In the below image, this means we’d print both the Cope and Drag Patterns, which would then be pinned and bolted onto a Match Plate (usually just a very flat aluminum plate). Normally these patterns cost thousands to ten thousands of dollars and months of lead time. Because of these limitations, the sand casting industry moves glacially slow compared to other industries which have adopted.

There are also opportunities to print patterns for runners, gates, risers and sprues which are often still made from hand-carved mahogany blanks. Yes, you read that right, a skilled operator must carve those by hand. Most of those parts are detailed in the image below but they essentially form a path for the liquid metal to flow from an entry point in the flask to the actual mold cavity.

Markforged Impacts on the Sand Casting Industry

Faster time to market

On both R&D/sample castings and low to medium volume production castings by 3D printing patterns (tooling). In the words of a customer “our sales team told us that we had a week to get one of our prospective customers sample parts of the [custom] job we were bidding on, or we might lose the bid. Even for rush tooling, it can take us 6 weeks to get a pattern made. With our X7, we can start printing patterns on Monday, begin pouring metal later in the week and have sample parts in hand by Friday”. R&D and low volume tooling is still often made from machined and polished aluminum, which has an extremely long lead time.

Opens up new business segments

By lowering the minimum order quantity required for the foundry to make a profit. A huge part of the cost of producing sand casted parts is the tooling required to make the flasks. Once the tooling is produced, the input cost per part is relatively low. In many cases, customers may decide to produce parts via other processes for low volume jobs because the cost of tooling is too high to amortize over such few parts. 3D printing patterns and other sand casting tooling allows foundries to be a cost-effective solution for their customers while preserving their margins and expanding their addressable market.

Be more competitive

By building a reputation for being agile and delivering results quickly. Foundries are typically not a fast-moving industry and their customers are forced to deal with long lead times stretching out into months from the time a PO is cut to the time a job is delivered. Foundries which adopt 3D printing, especially for tooling, gain a huge competitive advantage and are able to react to changes in demand or new business quickly.

Reduce warehousing costs

By reducing the amount of patterns stored for years that never get used. Foundries typically have huge warehouses of stored tooling in the case that a customer may want to re-order a job sometime down the road. In many cases, they will eat the cost of stored tooling for years before finally scrapping it during annual purges of their tooling warehouse. Reducing these warehousing costs can improve the profitability of their business.

Sand Casting Background

For an in-depth look into the sand casting process, see here.

Sand casting has been used for thousands of years to shape metal into useful forms.  At it’s most basic, it relies on the fact that the melting temperature of sand is significantly higher than that of common castable metals.  This means you can shape a mold out of sand into the negative of the part you want, pour liquid metal into it and let cool into a solid metal part.  The equipment, science and accuracy used in modern sand casting has changed significantly over those thousands of years, but fundamentally the process is the same.

There’s a few different types of sand casting that are in use today but Markforged can have the biggest impact on what’s known as matchplate sand casting.  This is where a part to be sand casted is split into two parts, generally along a plane called the parting line (more complex castings may have a non-planar parting line but it is less common).  A positive pattern for each half is precisely located on one side of a plate called the match plate.

Once the match plate is built, a box called a flask is placed around the plate and sand is packed against the pattern.  This produces a mold of one half of the part and then the process is repeated for the other side of the flask.  Channels called the gating system (gates, runners, risers, sprues) are often built directly into the match plate patterns as well (rather than created after packing the flask) to easily allow liquid metal to flow through the flask