Almost every engineering department has a script somewhere that took someone two full days to build, and that has been doing a five-minute job three times a year ever since. The opposite exists too: a work preparation colleague who burns half an afternoon every single week on the same clicking routine, because nobody ever worked out what that actually costs.
Automation has a price: building, testing, maintaining and explaining it to colleagues. You only earn that price back when a task returns often enough, takes long enough or fails expensively enough. This article gives you a decision rule that tells you per task, in a few minutes, whether automation is worth it: three thresholds, three recognizable examples and one trap. A toolbox like Thundercad pushes down the build cost side of that equation considerably, but the equation itself stays the same.
One boundary up front: this is about the decision per individual task. How you then add everything up and make the case to your manager is covered in The business case for CAD automation: how to build one that sticks.
Three thresholds: frequency, duration and cost of failure
Hold every candidate task against three measuring sticks. Threshold one is frequency: does the task come back at least weekly? A task that shows up every day may justify a solid solution; a task that surfaces twice a year justifies almost nothing. Threshold two is duration: does it take ten minutes or more per run, or does it consist of dozens of small actions that keep breaking your concentration? That last part counts too, because fragmented work costs more than the sum of its loose minutes. Threshold three is the cost of failure: what happens when it goes wrong once? A wrong revision reaching the shop floor is in a different league than a typo in an internal note.
The rule: if a task clears two of the three thresholds, automating is almost always worth it. If it clears one, it is a borderline case and you measure first. If it clears none, leave it alone. There is one exception: if the failure impact on its own is serious enough, think wrong files heading to production, that single threshold is sufficient.
Then do the simple math, in time rather than money. Assume, explicitly as an assumption: a task takes twenty minutes and occurs twice a week. At roughly forty-five working weeks, that is well over thirty hours a year. If automating it costs two days including testing and documentation, the investment pays for itself within a few months. The same math for a five-minute monthly task ends at one hour per year: there, the solution is allowed to cost next to nothing.
Example 1: exporting every drawing package by hand
A machine builder issues around sixty drawings per project, and every release means turning those into PDF for the shop floor and DXF for the sheet metal supplier. Done by hand, that is forty minutes of opening, exporting, naming and filing, with several releases running in parallel every week.
Against the measuring sticks: frequency cleared with room to spare, duration cleared, and the cost of failure is serious, because one forgotten sheet or one outdated revision in the package means wrongly cut material or a fitter standing idle. Three out of three thresholds: automate, and do it right away. This also happens to be exactly the kind of generic task you never need to build yourself: with Batch Publish in Thundercad you convert drawings in bulk to PDF, DWG, DXF and STEP, in one run instead of file by file.
Does exporting clear all three thresholds at your company too? Then there is nothing to build or maintain: Batch Publish is ready to go.
Try 30 days freeExample 2: the one-off archive job
A sheet metal company wants to rename four hundred legacy files and move them into a new archive structure. The temptation to script it is real: the work is dull, and scripting is more fun. But against the measuring sticks: the frequency is once, ever. The duration is substantial, one long afternoon, but singular. And the failure risk is manageable with a checklist and a backup copy made up front.
Zero to one thresholds cleared. The honest answer: just do it. Block an afternoon, work through the list with focus, and the job is finished before a script would have survived its first round of testing. Do be honest about that "one-off", though: a job that turns out to return every quarter is not a one-off but a recurring task, and then the verdict shifts.
Example 3: the borderline case with the title blocks
A work preparation colleague enters the order number and customer details into the title blocks of some fifteen drawings per order. Eight minutes per run, three orders per week on average. Frequency: cleared. Duration: just short. Cost of failure: a wrong customer name on a drawing is embarrassing, rarely disastrous. One to one and a half thresholds, depending on how strictly you count.
These are exactly the cases where you measure first and decide second. Gut feeling overrates the tasks that irritate and underrates the creeping ones; a week of tallying gives you the real number. How to go about that is described in Measure your own click work: tally for a week before you automate. And when in doubt, pick the cheapest solution that exists rather than the finest one imaginable: an existing tool or a smaller task beats a custom script that needs maintaining.
The three examples side by side:
| Task | Frequency | Duration per run | Failure impact | Verdict |
|---|---|---|---|---|
| Exporting drawing packages | Several times a week | Well over half an hour | High | Automate |
| One-off archive migration | Once | One afternoon | Low | Just do it |
| Title blocks per order | A few times a week | Eight minutes | Medium | Measure first |
The trap: automating what you should abolish
The most expensive automation is a perfect solution for a task that should not exist. The weekly overview nobody reads anymore, now landing in everyone's inbox automatically. The conversion between two file formats that is only needed because two departments never agreed on a single one. The retyping of data you could speed up, when you could also eliminate the double entry altogether.
So ask three questions about every candidate first, in this order:
- Why does this task exist, and who uses the outcome for what?
- Can the task disappear entirely, for instance through one agreement between two departments?
- Can the task shrink, so there is less left to automate?
Only when a task survives these three questions does it earn a run past the three thresholds. That order prevents you from adding speed to something that lacks direction.
Frequently asked questions
How do I know how often a task really returns?
Not from memory, because gut feeling exaggerates the irritations and misses the creeping work. Tally for one week, on paper or in a simple list, how often the task shows up and how long it takes. That single week of measuring prevents both unnecessary build projects and missed opportunities.
Does annoyance count when a task just misses the thresholds?
Yes, within reason. A task that keeps breaking your concentration at the busiest moments of the day costs more than the clock shows. But never let annoyance inflate the build cost: for these edge cases, pick a solution that costs next to nothing to set up and keep running.
Script it myself or use a ready-made toolbox?
If the task is unique to your company, custom work makes sense. If it is a generic task every Inventor department knows, such as exporting, saving or cleaning up, ready-made is almost always cheaper to run, because maintenance and updates are not on your plate. Finding out whether that holds for your own task list is free of strings: try Thundercad 30 days free.