The Cost of Jigs and Fixtures

Picking up where we left off

In this second installment we are going to investigate the cost to manufacture a clamping fixture with traditional machining, and then compare that cost to additive manufacturing with the use of SmartSliceIn the first blog post, the importance of jigs and fixtures in the industry was investigated, and a demonstration of how SmartSlice improves these parts was explored. There is a shift in the way fixtures are being manufactured, and additive manufacturing is becoming a cost-saving tool to produce these parts. The use of SmartSlice allows users to produce these parts with fewer print break cycles and improve print times and material usage. 

Following the previous blog post, the clamping fixture shown below has the following part requirements that will be used to compare the cost of traditional manufacturing with additive manufacturing and test if these printed parts can hold up to the user's demands. 

A quick review of the fixture part key requirements: 

  • The clamp is capable of applying a 900N force on the aluminum extrusion. 
  • The fixture holes must be capable of sustaining the 900N force. 
  • The max deflection can be no more than 1.5mm. 
  • The factor of safety must be 1.5 or greater. 
  • Must have a print time of 12 hours or less to limit assembly line downtime


 IMG_3593
Figure 1Clamping fixture

Fixture part cost using traditional manufacturing

The cost analysis started by reaching out to a machine shop in Denver Colorado to receive a quote and lead times to get the fixture shown in Figure 1 machined from aluminum. Unlike additive manufacturing, machining is a longer and more complex process that takes many machinist hours to produce a part. The machine shop that we reached out to quoted this relatively simple part with a 15 day lead time and a cost of $1,400. In order to meet our part replacement requirement for this exercise, we would also have to order a second part to have on hand in the event of needing to replace the part on the assembly line. An assembly line simply cannot wait 15 days to receive a replacement, so a spare part would have to be ordered and available. This results in a cost of $2,800 to have the fixture for the assembly line, and replacement when needed to minimize downtime.

Fixture part cost using additive manufacturing

Now that we have established a cost estimate for traditional manufacturing, we can compare that to the cost of using additive manufacturing. Our team estimates that there will be four main contributors to the cost of this 3D printed part.  

  1. The cost of material used to produce the part. 
  2. The cost of part preparation, which accounts for the time taken by the user to set up the printer and manufacture the part. 
  3. The associated initial printer cost with each part. 
  4. The associated infrastructure cost to operate the printer
     

Traditional Manufacturing 

  • Fixture machined from aluminum 
  • 15 - day lead time 
  • Price per part: $1,400 

 
 

Additive Manufacturing 

  • Fixture printed from Carbon Fiber Nylon 
  • Under 12 hour lead time 
  • Total part cost: $42.50 
  • Price per part (Material): $14.00 
  • Price per part (Preparation): $24.00 
  • Price per part (Printer): $3.80 
  • Price per part (infrastructure): $0.70 

When comparing the cost to manufacture a single part it becomes even more evident why additive manufacturing is being implemented in the industry. For our example clamping fixture the total cost to print the part in-house came to $42.50. This is dramatically more affordable when compared to our quoted cost of $1,400 to get the same fixture machined from aluminum. This price variation is very compelling for the argument to use additive manufacturing to produce this fixture. 

This cost estimate does not include the added cost if any revision must be made to the designed part. If the machined part requires any changes it has to be reordered from the machine shop with the same $1,400 cost and 15 day lead time. On the other hand, a revision to the printed part could be completed within the same day and implemented on the assembly line within hours. The biggest unknown cost factor is the lead time associated with these fixture parts. Often time is more valuable than the actual cost of the part, and that aspect of the cost evaluation only further drives the importance of using additive manufacturing with SmartSlice to produce these fixture parts. The lead time for many of these 3D printed parts falls within hours, and not within days and weeks. 

Virtual prototyping jigs and fixtures with SmartSlice

Clamp Fixture Optimization results
Figure 2: SmartSlice optimized results meeting part requirements 

The biggest question engineers have is, "Are these parts going to function as intended?". With SmartSlice users can quickly find the optimal combination of material and print settings for the load casestiffness, and strength requirements. This helps users better understand how to improve the capabilities of these parts while also keeping print times to a minimum. The validation and optimization SmartSlice provides users makes it a critical component of the 3D printing workflow. The use of 3D printing for jigs and fixtures is great, but the use of SmartSlice ensures the printed part will function as a viable replacement. The virtual experimentation available with SmartSlice reduces the number of print/break/redesign iterative cycles users are using now to find an optimized print setting. The optimized fixture shown in Figure 2 shows this part has a higher factor of safety and smaller max displacement than required. This fixture part will meet the requirements of the fixture while being produced at a much lower cost using additive manufacturing. The value of SmartSlice truly shines when analyzing the savings in print time and increased part performance with the fewest number of print break cycles.

FFF Cura SmartSlice Validation Optimization Jigs Fixtures