The Problem with Undocumented Processes
I’ve walked into shops where the same gun drilling job produces different results depending on which operator runs it. One operator runs 0.04 mm/rev feed and gets good parts. The next operator runs 0.07 mm/rev and scrap parts. Neither knows what the other is doing because there is no written standard. The scrap rate swings wildly between shifts and nobody can figure out why.
Undocumented processes make troubleshooting impossible. When a problem shows up on second shift, nobody knows what changed because nobody wrote down the baseline. The second-shift operator adjusts something, the problem goes away, and the fix is lost by morning. The same problem comes back the following week and the cycle repeats.
I have seen first-pass yield jump from 90% to 98% just by implementing standard setup sheets. The improvement is consistent across every shop where I have introduced process documentation.
Documentation Types
Deep hole drilling needs multiple types of documentation, each serving a different purpose. I maintain four distinct document types for every job.
| Document Type | Purpose | Length | Audience | Update Frequency |
|---|---|---|---|---|
| Job setup sheet | Machine parameters, tool spec, inspection criteria | 1 page | Machine operators | Every parameter change |
| Standard operating procedure (SOP) | Step-by-step process from setup to teardown | 3-5 pages | All shifts | Annual review or process change |
| Work instruction | Detailed task breakdown for specific operations | 1-2 pages per task | New operators, cross-training | As needed |
| Inspection checklist | Quality checks with acceptance criteria | 1 page | Inspectors, operators | Per job, updated with revisions |
| Troubleshooting guide | Common problems with root causes and fixes | 1-2 pages | All shifts, maintenance | Updated from real events |
| Training document | Process overview, safety, quality points | 2-4 pages | New hires | Annual |
The setup sheet is the most-used document. I keep it at the machine. The SOP and work instructions live in a digital folder that every operator can access from the shop floor terminal.
What I Document on the Setup Sheet
I use a single-page job setup sheet for every job. It covers the four categories that matter: machine parameters, tool specification, setup procedure, and troubleshooting.
| Category | What I Record | Example |
|---|---|---|
| Machine parameters | Speed, feed, coolant pressure, peck cycle | 3,200 RPM, 0.04 mm/rev, 60 bar |
| Tool specification | Diameter, type, coating, regrind count | 10 mm, gun drill, TiAlN, regrind #3 |
| Setup procedure | Bushing ID, pressure head position, alignment steps | Bushing 10.02 mm, gap 1.5 mm |
| Setup verification | Pilot hole depth, runout check, coolant flow test | Pilot 15 mm, runout < 0.005 mm |
| Inspection criteria | Diameter tolerance, surface finish, frequency | 10.00 +/- 0.05 mm, 1.6 Ra, every 10th part |
| Chip reference | Photo of acceptable chips | See attached photo |
| Troubleshooting | Top 3 problems with fixes | See section below |
I also list the three most likely problems and their fixes right on the sheet. A common entry might be “Chips not clearing → Check coolant pressure at tool tip, should be 60 bar minimum.” This saves operators time when something goes wrong.
SOP Template Structure
When I write an SOP for a deep hole drilling job, I follow a consistent structure. This makes it easy for operators to find the information they need regardless of which job they are running.
Section 1 — Job Identification: Part number, revision, material, machine assignment, required tooling list.
Section 2 — Setup Procedure: Steps in order — mount fixture, install bushing, load tool, set pressure head, align workpiece, run pilot. Each step includes the acceptance criteria (e.g., “Runout must be less than 0.005 mm TIR”).
Section 3 — Operating Parameters: Speed, feed, coolant pressure, peck cycle, depth. I include both the programmed values and the expected actual values.
Section 4 — In-Process Inspection: What to check, how often, acceptable range. First-part inspection requires 100% of features. Subsequent inspection at every 10th part checks diameter, surface finish, and straightness.
Section 5 — Troubleshooting: The three most common problems for this specific job, with root causes and corrective actions.
Section 6 — Change History: Date, change description, who approved it.
Creating the Documentation
I fill out a setup sheet during the first successful production run. I record the parameters as actually run, not as programmed. There is often a difference — the programmed feed might be 0.04 mm/rev but the actual feed rate measured over 10 seconds might be 0.038 mm/rev. The actual values are what matter for reproducing the process.
I photograph the chips from the first good part and tape the photo to the sheet. A new operator can compare their chips to the photo and know immediately if the process is right. This visual reference is more useful than a paragraph of text describing what chips should look like.
The sheet takes about 15 minutes to create. That investment pays back the first time someone needs to set up the job again.
The Documentation Station
The setup sheets, chip photos, and inspection records live in a three-ring binder mounted to the machine guard. No filing cabinets in the office. If it’s not at the machine, it won’t get used.
I also keep a master set of documentation in a digital folder on the network. If the binder gets lost or damaged, I print a new copy. The digital master gets updated whenever the process changes. I use a simple naming convention: part-number_revision_date.pdf.
Revision Control
Every document needs a revision number and a date. I use a simple system: Rev A for the initial release, then Rev B, C, etc. for changes. Each revision lists what changed and why.
When I update a document, I replace the binder copy immediately and archive the old version in a dated folder. The digital master gets the same treatment. This ensures nobody is working from an outdated setup sheet.
I review all job sheets annually. Jobs that haven’t run in 12 months get moved to an archive binder. Jobs still active get checked for accuracy. If a job has not changed in two years, I still review it — materials and tooling evolve, and the documented parameters might no longer be optimal.
Training Documentation
New operators need more than a setup sheet. I create a training document that explains the overall process: how the gun drill works, what the chips should look like, how to read the load monitor, and what to do when something goes wrong.
The training document includes photos of good parts, acceptable chips, and common defects. I walk every new operator through the document during their first week on the machine. After three months, I review the training with them and update the document based on questions they asked.
For more on training programs and operator certification, see my operator certification guide. I also cover SPC for deep hole drilling for shops that want to take process control to the next level.
The Impact
Standardized documentation eliminates the variation between operators. Every shift runs the same parameters and gets the same results. When something does go wrong, the troubleshooting section provides immediate guidance. First-pass yield on documented jobs in my shop runs above 98%. On undocumented jobs it hovers around 90%. That 8% difference represents significant scrap cost over a year of production.
The documentation also makes training faster. A new operator can read the setup sheet and understand the job in 15 minutes instead of spending a full shift shadowing an experienced operator.
Key Takeaways
- Document machine parameters, tool specs, setup procedure, and inspection criteria on a single-page sheet
- Use four document types: setup sheet, SOP, work instructions, and training documents
- Take a photo of chips from the first good part — a visual reference is better than text
- Keep the binder at the machine, not in an office — if operators can’t reach it, they won’t use it
- Update the sheet whenever a parameter changes, including the revision date
- Review all active job sheets annually and archive jobs that haven’t run in 12 months
- Standardized documentation improves first-pass yield from 90% to 98% in my experience