Can I Replace a Machine Part With a 3D Printed Version?

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David Helmers

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Introduction

Your old machine part fails. Spares are expensive, or worse, discontinued… Could 3D printing be the answer?

SUMMARY

Replacement parts are expensive due to OEM monopolies, overseas parts, and low production quantities. 3D printing can be a good option for replacing parts, especially when the parts are high complexity, low-medium quantity, and low load. It is best to avoid 3D printing when parts are exceptionally simple, high in quantity, and heavy load applications. 3D printing technology options range in quality, strength, colors, materials, and cost. If you want to replace your part with a 3D printed version, follow these steps:

  1. Reverse engineer the existing part
  2. Select the appropriate 3D printing process
  3. Then “slice” the part and print!

Why Are Replacement Parts So Expensive?

  1. OEM Monopolies – OEMs (Original Equipment Manufacturers) are typically the only suppliers for their replacement parts. This means that they can charge whatever they decide, because they have virtually no competition.
  2. Overseas Parts – Oftentimes, OEMs are located overseas. This increases the overall cost of the part because it needs to be shipped long distance to you. Tariffs, when applicable, also add to this cost.
  3. Low Production Quantities – If you are running a specialized piece of equipment, chances are the OEM does not make replacement parts in large batches. Using conventional manufacturing, smaller batches usually mean more expensive parts.

When is 3D Printing a Good Option for Replacement Parts?

  1. High Complexity: In 3D printing, low-complexity and high-complexity parts typically cost about the same, given that they are about the same size. This is because 3D printers print simply layer by layer. You don’t need any special tooling to get unique geometries.
  2. Low-Medium Quantity: Since 3D printing has such low tooling costs, low-medium quantity orders may be more affordable than machining, molding, and other methods that have higher tooling costs.
  3. Low Load: If your part is not dealing with heavy loads, you could potentially save yourself some money by replacing your machined part with a 3D printed one.

When is 3D Printing a Bad Option for Replacement Parts?

  1. Low Complexity: In this case, the programming, tooling, and setup costs are very low for machining and fabrication. These processes quickly become more cost effective than 3D printing.
  2. Very High Quantity: If you are producing very large quantities, 3D printing may end up being slower and more expensive. For plastic parts, processes like injection molding shine in this case.
  3. High Strength Applications: Most 3D printing processes produce plastic parts. And even when metal is 3D printed, it still cannot match the material properties of machined metals.

Example Scenarios and Decisions

  1. Sensor Mount Bracket – You have an existing assembly that was delivered with an injection molded sensor mount. You dropped the assembly, breaking off the sensor mount. Your options are:
    1. Buy the whole new assembly – $$$
    2. Design and machine a new bracket – $$
    3. Design and 3D print a new bracket – $
      • Medium-High complexity
      • Low quantity
      • Low strength
  2. Material Handling Puck – Your facility just started producing a new product. The product is transported around the plant in a puck fixture on a conveyor belt. You need 500 parts to get production started. Your options are:
    1. Injection Molding – $$$
    2. Machining – $$
    3. 3D Printing – $
      • Medium-High Complexity
      • Medium Quantity
      • Low Strength
  3. Button – Your company just designed a round plastic button that is widely used on many dress shirts. To keep up with production, you need to make 12,000 buttons a month. Your options are:
    1. 3D Printing – $$$
    2. Machining – $$
    3. Injection Molding – $
      • Low Complexity
      • High Quantity
      • Low Strength
  4. Lifting Hook – You need a custom lifting hook to go on your various hoists around the plant. They should be rated for 2000lbs. Your options are.
    1. 3D Printing – $
    2. Machining – $$
      • Low Complexity
      • Low-Medium Quantity
      • High Strength

What Are My Main Options for 3D Printing?

While this is not an exhaustive list, these are the major 3D printing technologies currently on the market. Split into 2 major categories, plastic and metal.

  • Plastic – Rigid & Flexible
    • FDM (Fused Deposition Modeling) – This is a process where plastic wire, known as filament, is molten through a small nozzle. The plastic is then deposited in layers onto a build plate.
      • Cost – $
      • Pros – Lots of material options, multi-color options, flexible material options.
      • Cons – Low resolution, Low strength, poor temperature resistance.
    • SLA (Stereolithography) – This is a process where liquid resin is cured using ultraviolet light. The resin is cured into layers on a build plate.
      • Cost – $$
      • Pros – Very high resolution, transparent options, flexible material options.
      • Cons – Low strength.
    • SLS (Selective Laser Sintering) / MJF (Multi Jet Fusion) – These are two very similar processes where plastic powder is deposited into layers and fused using either a laser or binder material.
      • Cost – $$
      • Pros – High strength, high resolution, flexible material options.
      • Cons – Limited material/color choices.
  • Metal
    • DMLS (Direct Metal Laser Sintering) – Like SLS, this process deposits powder into layers and fuses it using a laser.
      • Cost – $$$$
      • Pros – High Strength, high accuracy, lots of material options.
      • Cons – High cost, strength is still lower than machined metal.
    • Binder Jet – Like MJF, this process deposits powder into layers and fuses them using a binder material. These parts require sintering in a furnace after printing to ensure fusion.
      • Cost – $$$
      • Pros – Cheapest metal 3D printing process.
      • Cons – Low dimensional stability, strength lower than DMLS, fewer material options than DMLS.

How to Replace a Machine Part with a 3D Printed Version

These are the basic steps to follow when replacing a machine part with a 3D printed version. If you do not have the equipment or expertise to follow these steps. Resources like Wolfpack Workshop can do it for you. Click HERE to request a quote.

  1. Reverse Engineer the Existing Part – 3D printing requires a 3D CAD model to program the instructions to the machine. So, whether you obtain an existing model or make one yourself, this is the first step to replacing your machine part with a 3D printed version.
  2. Select a 3D printing process – See section titled “What Are My Options for 3D Printing?”. Once you select the process, the model may need to be altered or optimized for the selected process, while maintaining the critical features for proper function.
  3. “Slice” the Part and Print – All 3D Printers come with a software called a “slicer”. The slicer makes the plan that the machine follows to make the part. So, to print your part, you need to create the program using the slicer software, then send the job to the printer.

Wolfpack Workshop would love to help with your manufacturing needs any way we can. With quick lead times, extensive engineering experience, and reliable quality, we stand at the ready to help you achieve your goals. Contact us today or request a quote.

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Posted by

David Helmers