Questions with Michael Huggett

1. How do medical manufacturers benefit from fully machining parts in a single setup?

Whether starting with bar stock or blanks, there are huge advantages to establishing the capability to produce finished parts in one setup.

Part quality –It’s more challenging to maintain tolerances across multiple machines and manually moving a part from one machine to another introduces the potential for inaccuracy. Performing all processes on a single, high-quality machine ensures consistently high quality.

Agility – If parts are running across three machines each performing distinct processes, one machine going down effectively stops your production. If they’re running across three machines each performing every process, one machine going down still allows you to achieve 66% of your output.

Productivity – Moving parts from turning to milling to grinding creates a lot of unfinished WiP (work in progress) to manage. This slows throughput, eats up time, and creates waste that’s instantly eliminated if parts are fully processed on a single machine.

2. What type of machine is best-suited to single-setup production?

The three most impactful factors to consider when choosing a machine are a part’s size, design, and order quantity.

If a medical part has a length-to-diameter ratio of 6:1 or larger, it’ll be best suited to Swiss-type machining on a sliding headstock lathe.

A CNC multi-spindle should be considered for parts that: 1) have a length-to-diameter ratio of less than 6:1; 2) are no greater than 52mm (2.05") in diameter; 3) require at least 60% of their machining on the front or back; 4) are of medium or low complexity; 5) run in lot sizes of 5,000 or greater. Approximately 40% of parts currently running on sliding headstock lathes meet these criteria and could be produced far more cost effectively on a multi-spindle.

For medical components falling outside the previous two sets of conditions, a production turning center or CNC turn mill will prove optimal. Part complexity plays the most significant role in determining which is best for single-setup production of a given part.

3. What’s the cost of choosing the wrong machine type?

The cost can be significant. A U.S.-based medical manufacturer had been producing a specific medical component on a sliding headstock lathe. The total cycle time was 348 seconds. When they needed to expand capacity via a new machine, they discovered they could achieve a cycle time of 60 seconds on a CNC multi-spindle. Despite the machine investment being a little more than 4x as much, they achieved a per-part cost of $1.26 on the multi-spindle, compared to $1.68 on the alternative, resulting in a 25% cost savings.

Choosing the right machine goes beyond direct cycle time comparisons, though. For the manufacturer embracing single-setup production, a new purchase decision requires careful consideration of the current and expected part mix, as well as the existing machine fleet. The end goal is tackling your full range of parts while eliminating inefficiency and inaccuracy from flowing work-in-progress from one machine to another.

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