In high-volume machining, the true cost of a hole is rarely the price of the tool itself. It is machine downtime during tool changes, inconsistent hole quality across shifts, and the logistics of sending solid carbide drills out for regrinding. Iscar built the SUMOCHAM family to attack exactly these costs: an exchangeable-head drilling system in which the cutting head is a small, precision carbide component that can be replaced at the machine in under a minute, while the carrier body stays in the spindle.
This article explains how the SUMOCHAM system is put together, what makes the IC908 head grade versatile across material groups, how to choose between the main head geometry families, and which starting cutting parameters are realistic for steel, stainless steel and nickel-based superalloys.
What Is the SUMOCHAM System?
SUMOCHAM is Iscar’s exchangeable-head drilling platform, covering nominal diameters from 6.00 mm up to 32.99 mm with depth-to-diameter ratios of 1.5, 3, 5, 8 and 12 times the diameter. The drill body, made from hardened steel with polished internal coolant ducts, is a long-life component that may outlast dozens of heads. The carbide head carries the complete cutting geometry: point angle, chisel edge, primary and secondary clearances, and flutes that extend far enough into the body to guide the chip out of the hole.
The commercial logic is straightforward. A solid carbide drill is regrinded two to four times at best, and each regrind cycle takes the tool out of production for days while introducing diameter and geometry variation. A SUMOCHAM head is designed to be used once and then recycled, so every hole in a batch is produced by a fresh, factory-specification cutting edge. Head replacement happens at the machine, without presetting an entirely new tool and without re-establishing offsets beyond a minor length compensation.
System Architecture: Body, Seating and Clamping
The head locates on a precision-ground tapered seat that controls radial runout and axial position, and a central clamping screw locks it in place. Internal coolant ducts in the body exit through the head seat, so high-pressure coolant reaches the cutting zone even at 12xD depth. The connection is engineered to keep total indicated runout low, typically in the range of 0.02 to 0.03 mm at the head, which is what allows the system to produce holes close to IT8-IT9 tolerance in stable conditions.
Three practical points are worth respecting from the start:
- Seat cleanliness is critical. A single chip trapped between head and seat pushes runout out of tolerance and destroys hole quality. Wipe the seat and inspect the clamping screw at every head change.
- Torque matters. Tighten the screw to the catalog torque with a torque-controlled key. Undertightening lets the head micro-move under load; overtightening damages the seat and threads.
- Bodies are not consumables. Inspect the body wear lands and coolant exit holes periodically, especially after machining HRSA materials at 8xD and deeper where pressure and temperature are highest.
IC908: One Grade, Many Geometries
Unlike brands that fragment their drill range into dozens of grades, Iscar concentrates most SUMOCHAM heads in a single workhorse grade: IC908. The substrate is an ultra-fine, sub-micron carbide with a relatively high cobalt content, giving the transverse rupture strength needed to survive interrupted cuts and the edge strength needed at heavy feeds. The coating is a multilayer TiAlN-based PVD applied with a smooth surface finish that lowers friction against the chip, resists built-up edge in gummy austenitic stainless steels, and holds up across a wide temperature envelope.
This reflects a deliberate philosophy: the grade carries the wear resistance and toughness, while the head geometry family carries the application specificity. For the shop floor it simplifies inventory dramatically. One grade code is stocked, and selection happens at the geometry level rather than the substrate level.
Head Geometry Families
Within the IC908 grade, SUMOCHAM heads are organized into geometry families, each tuned to a material group and cutting condition. The families most often specified are summarized below.
| Head family | Primary application | Geometry character | Typical use case |
|---|---|---|---|
| HCP | Steel, cast iron | Universal geometry with a strong honed edge and polished margins | General-purpose drilling in alloyed and unalloyed steels; the default choice when no special condition applies |
| ICP | Long-chipping steels | Sharp, high-penetration point with highly polished flutes | Low-carbon and medium-carbon steels where chip control and reduced thrust matter |
| HNP | Stainless steel, HRSA | Tougher edge preparation balanced for work-hardening materials | Austenitic and duplex stainless steels, nickel alloys, titanium alloys |
| IHCP | Interrupted cuts | Reinforced cutting edge and strengthened corner | Cross holes, cast skin, slotted or pre-machined entry conditions |
Availability of each family depends on diameter and depth ratio, and larger diameters offer the widest selection. When in doubt between two families, the universal HCP head is the safer starting point; geometry specialization can be introduced once the application behavior is understood.
Recommended Starting Cutting Parameters
The values below are realistic mid-range starting points for SUMOCHAM heads in IC908, assuming rigid workholding, through-spindle coolant at adequate pressure and stable entry conditions. Feed values are given in mm per revolution for three diameter bands. Always confirm against the current Iscar catalog for the exact diameter, head family and depth ratio.
| Material group | Typical example | Vc (m/min) | f, Ø6-10 mm | f, Ø11-18 mm | f, Ø19-33 mm |
|---|---|---|---|---|---|
| Unalloyed steel, under 700 N/mm2 | S235, S45C, C45 | 100-130 | 0.18-0.24 | 0.26-0.34 | 0.32-0.44 |
| Alloyed steel, 850-1000 N/mm2 | 42CrMo4, AISI 4140 | 85-110 | 0.16-0.22 | 0.24-0.32 | 0.30-0.40 |
| Austenitic stainless steel | 304, 316, 1.4301 | 55-80 | 0.12-0.18 | 0.18-0.26 | 0.22-0.32 |
| Duplex stainless steel | 2205, 1.4462 | 45-65 | 0.10-0.16 | 0.16-0.24 | 0.20-0.28 |
| Grey cast iron | GG / GJL | 110-160 | 0.22-0.30 | 0.32-0.44 | 0.40-0.55 |
| Nickel superalloy | Inconel 718, aged | 22-35 | 0.06-0.10 | 0.10-0.15 | 0.12-0.18 |
| Titanium alloy | Ti-6Al-4V | 35-55 | 0.08-0.14 | 0.14-0.20 | 0.18-0.26 |
- Coolant pressure: a minimum of 10 bar for steels; 20 bar and above is strongly recommended for HRSA and titanium alloys, and for all deep holes beyond 5xD.
- Tuning order: start at mid-range Vc and feed. Increase feed first as long as chip form, power and hole quality allow, then adjust Vc according to observed wear.
- Entry conditions: on inclined or curved surfaces reduce feed by 30 to 50 percent until full engagement; on cast skin reduce feed until the head is fully in the material.
- Deep holes: for 8xD and 12xD bodies, reduce the feed by roughly 10 to 15 percent and verify chip evacuation before running at full rate.
SUMOCHAM Compared With Competing Exchangeable-Head Systems
The exchangeable-head drill class is contested by every major cutting tool manufacturer, and the systems differ more in philosophy than in raw capability. The table below positions SUMOCHAM against its main rivals.
| System | Head diameter range | Depth ratios | Defining character |
|---|---|---|---|
| Iscar SUMOCHAM | 6.00-32.99 mm | 1.5x to 12xD | One-grade IC908 philosophy with a broad spread of geometry families |
| Sandvik CoroDrill 880 | Approx. 6-33 mm | Typically 3x to 8xD | Long-established benchmark with documented hole-quality data across a wide grade range |
| Tungaloy TungMeister | Approx. 6-33 mm | Typically 3x to 8xD | Compact body design and strong availability in Asian markets |
| Mitsubishi MYSX | Approx. 5-30 mm | Typically 3x to 8xD | Competitive head pricing with stable general-purpose performance |
For a mixed-batch job shop, SUMOCHAM stands out on inventory simplicity: a single grade code and a handful of head families cover steel, stainless and HRSA work. The fast head indexing at the machine also favors lights-out operation, where a failed drill at 3 a.m. costs far more than the head itself. The CoroDrill 880 remains the reference many procurement teams default to for process security, while TungMeister and MYSX compete strongly on head cost in high-volume commodity drilling.
Best Practices for Reliable Performance
- Toolholding: use hydraulic, shrink-fit or precision milling chucks. Side-lock holders introduce runout that the head connection cannot compensate for, particularly below 10 mm diameter.
- Coolant filtration: fine filtration protects the small ducts in the head seat; clogged exits are a common root cause of premature head failure in HRSA work.
- Machine orientation: vertical spindle drilling lets gravity help chip evacuation. On horizontal machines, verify through-spindle coolant pressure before scaling up feeds.
- Wear policy: index heads at approximately 0.2 to 0.3 mm flank wear depending on diameter and material, rather than running to fracture. A snapped head left in a 12xD hole can scrap the part.
- Chip signature: target short, controlled chips. Long ribbons indicate insufficient feed; fine powder in superalloys indicates excessive Vc.
Troubleshooting Quick Reference
| Symptom | Likely cause | Corrective action |
|---|---|---|
| Rapid corner chipping | Feed too high for the edge prep, or interrupted cut | Reduce feed by 20 percent; switch to a reinforced head family |
| Built-up edge in stainless | Vc too low, insufficient coolant | Raise Vc by 10-15 percent; check coolant concentration and pressure |
| Hole oversize, poor roundness | Dirty seat, worn body or holder runout | Clean the seat, replace the screw, verify runout at the head |
| Long unbroken chips | Feed too low for the material | Increase feed in 10 percent steps while monitoring power |
| Crater wear, burnt head | Vc too high for an HRSA alloy | Reduce Vc by 20-25 percent and confirm coolant reaches the tip |
Frequently Asked Questions
Can SUMOCHAM heads be regrinded?
No. The heads are designed as single-use precision components with a recycling program behind them. The cost model assumes fresh geometry on every hole, which is also what keeps hole quality repeatable across the batch.
What hole tolerance can the system hold?
With clean seating, controlled runout and stable clamping, IT8-IT9 is realistic in most ductile materials. For tighter tolerances, follow the drilling operation with a reaming pass on the same machine.
Is a pilot hole required at 12xD?
No. SUMOCHAM is engineered to drill from solid across its full depth range, provided the machine is rigid and coolant pressure is adequate. A center drill is only useful on machines with questionable spindle alignment.
Conclusion
SUMOCHAM is less a drill than a drilling system: a durable steel body, a patented head connection and a single versatile grade expressed through a family of geometries. For shops drilling mixed materials at volume, the combination of seconds-long head changes, repeatable hole quality and simplified inventory is often worth more than any single improvement in cutting speed. Start with the HCP family at mid-range parameters, respect the seat and torque discipline, and the system will typically deliver predictable cost per hole across steel, stainless and superalloy work.
