The Business Impact of Post-Processing After 3D Printing: What You Need to Know
As soon as parts enter the post-processing phase, the automated, push-button process becomes a manual operation.
The perception and promise of 3D printing are that it offers a digital workflow that is simple, fast and automated; a process where complexity is free. That perception is generally correct up to the moment that parts are removed from the 3D printer. As soon as parts enter the post-processing phase, the automated, push-button process becomes a manual operation that impacts time, cost and quality.
Post-Processing: 3D Printing’s Dirty Little Secret
Post-processing encompasses all the actions that are performed after parts are removed from a 3D printer. There are two categories of post-processing, primary and secondary.
Primary post-processing includes the mandatory steps that must be performed on all parts to make them suitable for use in any application. The steps vary by technology but generally include cleaning and support structure removal. This article focuses solely on primary post-processing.
Secondary post-processing includes optional part finishing that improves the aesthetics or function of the part, including sanding, filling, priming and painting.
Six global manufacturing companies across industries contributed their post-processing experiences as input for this analysis.
According to these companies, prospective users should plan for one hour of post-processing for every one to six hours of 3D printing. This translates to a 17% to 100% increase in the total process time. However, the total elapsed time will often have a much larger increase. All the companies noted that time is dependent on the intricacy, or complexity, of the part.
Staffing is another consideration for prospective users. The companies reported that the ratio of machine operators to part finishers, the employees that do the post-processing, ranges from 1:1 to 1:3.
Facilities must also be considered. When providing ample room for the required equipment and workspace to conduct post-processing, these companies report that they have floorplans that use one-half to one square foot for post-processing for each square foot of 3D printer space.
Impact: Primary Issues
It comes as no surprise that the biggest issues with post-processing are the added cost and added time, which can be quite significant. Both time and money were noted by the six contributing companies as their primary concerns. However, the ranked priority for each varied and were driven by the current climate within the businesses. For example, cost was secondary for those that urgently need to accelerate delivery of 3D printed models and prototypes.
Post-processing adds cost to 3D printing operations in several ways, but the most-cited aspect is labor cost. Using a fully burdened labor rate, the companies reported an hourly cost of $30 to $100. With four to 10 3D printers, the annual labor cost, fully burdened, ranged from $100,000 to $500,000.
This equates to a direct labor cost for post-processing of roughly $25,000 to $50,000 per year for each 3D printer. If the machine operator, or another higher-wage employee, performs post-processing, the annual cost can rise significantly.
When adding a 3D printer, this burdened labor costs must be included in annual operating budgets. The additive manufacturing technology leader at a medical device company said that when budgets are taken into consideration, “Adding one more parts finisher means that there is one less machine that I can purchase.”
For those that are already saddled with post-processing labor, the benefit of eliminating this task may not be cost reduction. Instead, it could be capability expansion. Considering budgetary limits that preclude hiring, the contributors indicated that they would reallocate the post-processing staff to value-added activities.
Another expense element related to labor is the increased cost for models and prototypes when demand exceeds the capacity of the post-processing team. An engineering manager at a consumer products company noted that during peak periods he may have the needed 3D printer capacity but lack the required post-processing resources. In these situations, he either must pay for overtime or subcontract the work to a service bureau. He noted, “Outsourcing increases the part cost by three or four times, and we can’t deliver as fast as if we kept the work in-house.”
A key benefit of 3D printing is speed so anything that slows the process is undesirable. Although a single part may be post processed quickly, the aggregate effect can extend lead times by days or weeks.
As the contributors shared, post-processing adds 17% to 100% to 3D printing time on a batch-by-batch basis. What those numbers do not reflect is the full impact of this manual, bottleneck operation on schedules. A few hours of post-processing can translate to a 24-hour delay, even with a well-staffed operation. When compounded across multiple design iterations and multiple engineers, the delay can be measured in weeks and months.
Eliminating post-processing would dramatically accelerate the product development process, which in turn can reduce the time to market.
Another factor that adds to the potential for delays is that post-processing can be a bottleneck that is subject to backlogs. The automated 3D printing process typically outputs many parts per build, which all enter post-processing at the same time. Considering the need for direct labor and access to supporting equipment, parts wait in queue until the resources become available.
The automotive company noted that the bottleneck becomes very evident following a long holiday weekend. Leveraging the unattended operations, as many parts as possible are nested to print in one long run over the three days.
However, post-processing resources are overloaded when work resumes. A casting engineer at the company said, “There are backlogs even if post-processing is automated. Sometimes the post-processing equipment simply doesn’t have the throughput or capacity to match that of 3D printers running over multiple days.”
Without post-processing, the value of 3D printing could increase substantially. For some, it would allow them to perform more value-added tasks to improve part quality and expand the application base. For others, it would dramatically accelerate the total process, which increases responsiveness and total throughput. For those adding new 3D printers, eliminating post-processing would reduce labor expense by $25,000 to $50,000 for each machine. However, post-processing’s burdens don’t stop with labor cost and total process time.
Impact: Secondary Issues
While considered to be secondary issues by the six companies, the impact on quality, staffing, facilities and safety cannot be ignored.
Ultimately, the quality of 3D printed parts is in the hands of the part finishers that wield X-Acto knives, sandpaper and spray nozzles for media blasting or water jetting.
For those that have the budget to hire post-processing personnel, the issue becomes one of finding the right talent. According to a consumer product company’s engineering manager, “Post-processing is kind of an art form.” Part finishing requires a unique skill set and a unique personality.
Floor space is required to house the staff, workbenches and post-processing equipment. As stated earlier, a ratio of one-half to one square foot per square foot of 3D printer space will be needed in many cases. This space can be an impediment for those that don’t have an option to expand into existing areas; an expense for those that must take on construction; or an ongoing cost for those that have internal cross-charges for floor space used by the department.
Another cost consideration is the purchase of the workbenches and equipment, which will run into the thousands of dollars for the typical, yet small, 3D printer lab. There is also the additional cost to run utilities, such as electrical, water and air lines, to the equipment.
Safe operations, handling and disposal are sources of hidden costs that many do not account for until after the implementation of a 3D printer. Additionally, proper disposal of hazardous waste, generated during post-processing, is quite costly.
In a lab environment, the issues and limitations created by post-processing are impediments to throughput and part quality, as well as a drain on budgets and resources. In a design or engineering area, these issues are significant barriers to adoption.
Three of the six companies expressed an immediate desire to deploy 3D printing in office areas while maintaining the existing 3D printing lab. The advantage of distributed 3D printing is that a designer or engineer would have quicker turnaround—both for office-built and lab-built parts. Placing 3D printers in the office is more responsive because it sidesteps the work queue of the lab. Meanwhile, the lab is more responsive because it offloads the work for basic models and prototypes.
Yet, all agree that office deployment is not reasonable when primary post-processing is required. For 3D printing in the office to become realistic, a single device must output ready-to-use items with no requirement for additional labor, equipment and floor space.
Post-processing is a non-value-added function that is both a burden and a bottleneck. Without it, the promise of a simple, fast and automated digital workflow becomes a reality for all parts, whether simple or complex in design. In that new reality, 3D printing adoption will accelerate, and the breadth of applications will expand—for organizations of all types and sizes and for every industry and market.