How to make CAM Assist's cycle time estimates match what actually happens on your machine.
What the Scale factor does
The Scale factor adjusts CAM Assist's calculated cycle time so it lines up with the real machining time you see at the spindle. The calculation alone can't account for everything a physical machine does — acceleration and deceleration on every move, dwell, tool changes, and the general efficiency of the equipment — so the estimate often runs a little short or long. The Scale factor closes that gap.
It's a simple percentage multiplier applied to the estimate. At 100% the estimate is left exactly as calculated. At 150% every estimate is multiplied by 1.5. So if CAM Assist estimates 20 minutes but the part really takes 30, a Scale factor of 150% brings the report in line.
Where to find it
The Scale factor lives in a machine's settings, so each machine can carry its own value — useful when your machines run at different real-world speeds.
Leave the field blank or set it to 100% if you don't want any adjustment. Whatever you enter applies to every estimate CAM Assist produces for that machine.
How to work out the right value
You don't have to guess. Run one part through CAM Assist with the Scale factor switched off, compare the estimate against a time you trust, and let the numbers give you the percentage.
- Set the Scale factor to 100% (or leave it blank). This gives you CAM Assist's raw, unadjusted estimate — the number you'll be correcting.
- Run CAM Assist on a representative part and note the cycle time it reports. Call this the CAM Assist estimate.
- Get a reference time you trust for the same part. This is usually the cycle time from your CAM package after posting the toolpaths, but it can also be an actual measured run on the machine. Call this the reference time.
- Divide the reference time by the CAM Assist estimate, then multiply by 100. That's your Scale factor.
- Enter the result in the Scale factor field and re-run. The reported time should now match your reference.
The calculation
This is the "cross multiplication" written out. You're solving a proportion: the CAM Assist estimate is to 100% as the reference time is to the Scale factor you want.
Rearranged, that's:
9:36 is 9 min 36 s = 576 seconds = 9.6 minutes.Examples
Example 1 — the basic case
CAM Assist estimates 20:00. The part actually takes 30:00 on the machine.
Scale factor = (30 ÷ 20) × 100 = 150%
The estimate was running short, so you scale it up.
Example 2 — reference time from the CAM package
With the Scale factor at 100%, CAM Assist reports 24:00. Your posted CAM package program for the same part comes out at 30:00.
Scale factor = (30 ÷ 24) × 100 = 125%
Example 3 — when the estimate runs long
CAM Assist reports 12:00, but your reference time is only 9:36 (9.6 minutes).
Scale factor = (9.6 ÷ 12) × 100 = 80%
Here the estimate was too high, so a value below 100% pulls it down.
Example 4 — working in seconds
CAM Assist estimate 18:45 (1,125 s). Reference time 22:30 (1,350 s).
Scale factor = (1,350 ÷ 1,125) × 100 = 120%
Quick reference
| CAM Assist estimate | Reference time | Calculation | Scale factor |
|---|---|---|---|
| 20:00 | 30:00 | 30 ÷ 20 × 100 | 150% |
| 24:00 | 30:00 | 30 ÷ 24 × 100 | 125% |
| 12:00 | 9:36 | 9.6 ÷ 12 × 100 | 80% |
| 18:45 | 22:30 | 1350 ÷ 1125 × 100 | 120% |
Tips for a reliable factor
- Use a part that's typical of what you run on that machine. A factor tuned on an unusual part won't generalise well.
- Calculate per machine. A fast, high-power machine and an older, slower one will need different factors, and the setting is stored against each machine for exactly that reason.
- For a steadier number, average the result across two or three parts rather than relying on a single one.
- Revisit the factor if you change tooling strategy, feeds and speeds, or the machine itself — the gap it corrects for can shift.
FAQ
What happens if I leave the Scale factor blank?
CAM Assist treats it as 100% and reports the raw estimate with no adjustment.
Can the Scale factor be below 100%?
Yes. If CAM Assist over-estimates, a value under 100% scales the reported time down (see Example 3).
Does it change my toolpaths or machining strategy?
No. The Scale factor only affects the reported cycle time in the estimate. It doesn't touch the toolpaths, feeds, speeds, or anything the machine actually does.
Which reference time should I use — the CAM package or a real machine run?
Either works. The posted CAM package time is the most convenient and repeatable. A measured run on the machine is the most accurate. Use whichever you trust more for that machine.