The chip conveyor is the most abused component on a deep hole drilling machine. It handles hot, sharp, abrasive chips under a continuous stream of coolant. When it works, chips are removed automatically. When it jams, the machine stops and someone spends an hour with a hook and a coolant hose clearing the mess.
Chip Conveyor Types for Deep Hole Drilling
Conveyor Comparison
| Conveyor Type | Best For | Chip Types | Advantages | Disadvantages |
|---|
| Hinged steel belt | General purpose, all sizes | All types, including long stringy | Durable, handles heavy loads | Can jam with stringy chips |
| Scraper (drag) | Fine chips, small particles | Broken chips, fines | Low cost, simple | Cannot handle long chips |
| Magnetic | Ferrous chips only | Steel and iron fines | No moving parts in coolant | Ferrous only, not for stringy chips |
| Screw (auger) | Small machines, limited space | Short broken chips | Compact, enclosed | Jams easily, hard to clear |
| Filter belt | Fine chips with high coolant flow | Very fine chips, powder | Combined filtration and removal | Slow, not for large chips |
Tip: For deep hole drilling, the hinged steel belt conveyor is the most common and reliable choice. It handles the high volume and variety of chip types that deep hole drilling produces. Ensure the conveyor pitch and hinge design are specified for the largest chip size your process produces.
Common Conveyor Jam Causes
| Cause | Mechanism | Frequency | Prevention |
|---|
| Stringy chips wrapping around hinge pins | Long, unbroken chips tangle in belt joints | Very common | Improve chip breaking, increase feed rate |
| Large chip accumulation at discharge | Chips pile up at exit, block belt movement | Common | Increase discharge height, add chip bin sensor |
| Fines packing between belt segments | Fine particles wedge into belt gaps | Common in gun drilling | Use proper belt pitch for chip size |
| Broken insert or tool fragment in belt | Hard fragment jams between belt and housing | Occasional | Magnets at conveyor entry to catch fragments |
| Belt tension too loose | Belt slips on drive sprocket | Occasional | Check tension monthly |
| Drive motor overload | Excessive chip load or blockage | Occasional | Install torque limiter or current monitoring |
| Coolant flow carrying chips back | Coolant recirculation pushes chips under conveyor | Less common | Check coolant return flow path |
Preventive Maintenance
Daily Checks
| Check | Location | What to Look For | Action |
|---|
| Chip flow at discharge | Conveyor exit | Chips discharging freely | If not flowing, check for jam |
| Belt movement | Full length | Smooth, continuous motion | If jerky or stopped, investigate |
| Coolant flow over belt | Along conveyor | Even coolant flow | If pooling, check drain |
| Unusual noise | Drive motor, belt | Grinding, clicking, squealing | Stop and inspect |
Weekly Maintenance
| Task | Detail | Time Required |
|---|
| Inspect belt for wear | Check hinge pins, side chains, belt plates | 15 minutes |
| Check belt tension | Adjust if belt slips on drive sprocket | 10 minutes |
| Clean discharge area | Remove accumulated chips at exit | 10 minutes |
| Inspect drive chain (if applicable) | Lubricate, check tension | 10 minutes |
| Check coolant return screen | Clean screen at conveyor entry | 5 minutes |
Monthly Maintenance
| Task | Detail | Time Required |
|---|
| Remove and clean belt (if possible) | Full cleaning of belt segments | 2–4 hours |
| Inspect sprockets for wear | Check tooth profile, replace if worn | 15 minutes |
| Check bearing condition | All conveyor shaft bearings | 15 minutes |
| Test torque limiter (if equipped) | Verify protection setting | 10 minutes |
| Inspect chip bin level sensor | Clean sensor, verify operation | 10 minutes |
Quarterly Maintenance
| Task | Detail | Time Required |
|---|
| Replace worn belt segments | Segments with cracked or worn hinge loops | 2–4 hours |
| Replace drive chain and sprockets | If chain stretched or sprockets worn | 1–2 hours |
| Clean conveyor housing interior | Remove accumulated fines from housing bottom | 2–4 hours |
| Inspect and lubricate all bearings | Replace if rough or noisy | 30 minutes |
| Check motor and gearbox | Oil level, unusual noise, temperature | 30 minutes |
Jam Clearing Procedure
Step 1: Safety
| Step | Action | Reason |
|---|
| 1 | Stop the conveyor | Never attempt to clear a jam with the conveyor running |
| 2 | Lock out conveyor power | Prevent accidental startup |
| 3 | Wear heavy gloves | Chips are sharp, coolant is slippery |
| 4 | Have a coolant hose ready | Flush chips away from jam point |
Step 2: Identify Jam Location
| Symptom | Likely Location | Access Method |
|---|
| Belt not moving, motor running | Drive sprocket or discharge | Open discharge cover |
| Belt not moving, motor stalled | Any point along belt | Inspect full length |
| Belt moving but no chips at exit | Internal jam at mid-point | Open access covers along housing |
| Unusual noise at drive end | Drive chain or sprocket | Inspect drive mechanism |
| Chips backing up at entry | Blockage near chip entry point | Open entry access door |
Step 3: Clear the Jam
| Jam Type | Clearing Method | Tools |
|---|
| Stringy chips wrapped on hinge | Cut chips with snips or saw | Tin snips, utility knife |
| Chip pack in housing | Flush with coolant hose, hook out | Coolant hose, chip hook |
| Broken insert wedged in belt | Remove insert with pliers | Pliers, screwdriver |
| Large chip stuck in discharge | Break chip with hammer or pull out | Hammer, tongs |
| Belt jammed on housing | Pry belt loose, check for damage | Pry bar |
Step 4: Verify and Restart
| Step | Action |
|---|
| 1 | Remove all loose chips from conveyor area |
| 2 | Rotate conveyor by hand (with power off) to verify free movement |
| 3 | Check for belt damage from the jam |
| 4 | Restore power, jog conveyor to verify smooth operation |
| 5 | Run empty for 1–2 minutes before resuming production |
Warning: Never use the conveyor drive motor to clear a jam by jogging. If the belt is wedged, jogging the motor can shear pins, strip gears, or snap the drive chain. Always clear the jam manually with power locked out.
Jam Prevention by Chip Management
Chip Breaking for Conveyor Compatibility
| Chip Type | Conveyor Impact | Recommended Chip Length | Action |
|---|
| Stringy > 50 mm | High jam risk | < 15 mm | Increase feed, improve chip breaker |
| C-shape 3–8 mm | Low jam risk | Ideal | Maintain current parameters |
| Needle < 2 mm | Moderate — can pack | 2–5 mm | Reduce feed slightly |
| Powder/dust | High — packs in housing | Avoid | Check coolant pressure, tool condition |
Conveyor Modifications for Problematic Chips
| Modification | Benefit | Cost | Installation Complexity |
|---|
| Increased belt pitch | Handles larger chips, less jamming | Moderate | New belt required |
| Chip crusher at conveyor entry | Breaks large chips before conveyor | High | Significant modification |
| Magnetic separator before conveyor | Removes ferrous fines | Moderate | Plumb before conveyor |
| Fines removal screen | Separates fine chips from coolant return | Low | Screen in coolant trough |
| High-torque drive | Handles heavy chip loads better | Moderate | Motor and gearbox upgrade |
Conveyor Drive Maintenance
Drive Component Checks
| Component | Check Frequency | Failure Mode | Prevention |
|---|
| Gearbox oil level | Monthly | Low oil causes gear wear | Maintain oil level, change annually |
| Drive chain tension | Monthly | Chain stretch, slip | Adjust tension, replace at wear limit |
| Torque limiter | Monthly | Corrosion, stuck | Clean, test operation |
| Motor cooling fan | Monthly | Clogged with chips | Clean fan cover |
| Drive sprocket | Quarterly | Tooth wear from chain | Replace when teeth sharpen |
| Bearings | Quarterly | Seal failure, contamination | Replace if noisy or rough |
FAQ
Why does my chip conveyor keep jamming?
The most common cause is stringy chips — long, unbroken chips wrap around hinge pins and belt segments, gradually binding the conveyor until it stops. Fix the chip breaking in the drilling process (increase feed rate, optimize chip breaker geometry) and the conveyor jams will decrease.
How often should I clean the chip conveyor?
Clean the discharge area weekly and perform a full conveyor cleaning monthly. In high-production BTA drilling, increase to weekly full cleaning. The chip accumulation inside the conveyor housing is the second most common cause of jams after chip shape problems.
What type of chip conveyor is best for deep hole drilling?
Hinged steel belt conveyors are the industry standard for deep hole drilling. They handle the high volume, heavy weight, and variety of chip types that BTA and gun drilling produce. For very fine chips from gun drilling, a scraper conveyor with a magnetic separator may be a better choice.
Can I modify my conveyor to handle stringy chips?
Yes, the most effective modification is to increase the belt pitch (distance between hinge pins) so that stringy chips are less likely to wrap around the pins. A chip crusher at the conveyor entry can also break long chips before they reach the belt. However, fixing chip shape at the cutting edge is always preferable to modifying the conveyor.
How do I clear a jammed chip conveyor safely?
Lock out the conveyor power, wear heavy gloves, and manually remove the obstruction. Never attempt to clear a jam with the conveyor running — the belt can pull hands into the drive sprocket. Use a coolant hose to flush chips away and a chip hook to pull out packed material.
A chip conveyor that runs reliably is the result of good chip breaking and regular maintenance. Fix the chip shape at the cutting edge first, then maintain the conveyor on schedule. This article reflects industry practice as of 2026.
