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Walnut Shell vs Corncob: How to Choose Dry Tumbling Media for Eyewear, Jewelry & Hardware Dry finishing media selection guide • Walnut shell & corncob • For dry tumbling, vibratory and centrifugal lines Dry organic media — crushed walnut shell and ground corncob — is the workhorse of dry tumbling and dry vibratory finishing. The two materials look similar in the bag, but they behave very differently in the bowl. Choosing the wrong one usually shows up as dull surfaces, stuck-on compound, or parts that are clean but not bright. This guide explains what each media does, how they compare, and how to pick the right grade for eyewear, jewelry, and precision hardware. Walnut shell vs corncob: material character, absorbency, grit ranges and typical applications Rule of thumb. Walnut shell cuts and brightens — use it when you need to remove marks, light oxides, or burrs while building gloss. Corncob dries and polishes gently — use it to absorb oils and polishing compound while producing a soft, streak-free luster on delicate parts. 1. What Dry Media Actually Does In a dry process there is no water or chemical solution doing the work. The media itself performs three jobs at once: it abrades (removing burrs, tool marks, and light tarnish), it carries compound (holding polishing wax against the workpiece), and it absorbs (soaking up oils, fingerprints, and spent compound so parts come out clean and dry). How aggressively a media abrades — and how well it absorbs — is exactly where walnut shell and corncob differ. 2. Walnut Shell Media: Character and Best Uses Walnut shell is crushed hard shell, typically from English walnuts. It is noticeably harder and sharper at the particle level than corncob, which makes it a light-cutting media rather than a pure polishing media. Walnut shell dry finishing media — hard, micro-cutting granules Light cutting action: removes light burrs, parting lines, tarnish, and heat-tint discoloration on metals and hard plastics. Gloss building: on brass, aluminum, zinc, and acetate it develops a bright, uniform sheen over 2–8 hour cycles as a typical starting range. Durable and reusable: holds its structure longer than corncob, so it suits longer production runs before replacement. Typical grades: coarse grits (6#–20#) for cleaning and deburring; finer grits (24#–40#) for smoothing and pre-polish. 3. Corncob Media: Character and Best Uses Corncob is the ground core of dried corn cobs — a soft, highly porous organic media. It cuts very little; its strengths are absorption and a gentle, burnishing polish. Corncob dry finishing media — soft, highly absorbent granules Gentle polishing: smooths micro-roughness and raises a soft luster without rounding edges or marking threads. Excellent absorbency: soaks up polishing wax, oils, and water — the standard choice for the final drying-and-gloss stage after wet finishing. Safe on delicate parts: the go-to media for jewelry, watch components, acetate eyewear, and painted or plated surfaces. Typical grades: medium (12#–20#) for general drying and polish; extra fine (30#–40#) for mirror-stage work on soft materials. 4. Side-by-Side Comparison Property Walnut Shell Corncob Cutting action Light to moderate — removes marks and tarnish Minimal — burnishing and smoothing only Absorbency Good Excellent Surface effect Bright, clean, slightly satin-to-gloss Soft, deep, streak-free luster Edge condition Lightly softened Preserved Media life Longer — resists breakdown Shorter — dusty as it wears Typical grit range 6# – 40# 12# – 40# Best applications Hardware, brass/aluminum parts, acetate frames, deburr + gloss Jewelry, watch parts, eyewear final gloss, drying after wet work 5. Pairing Media, Compound and Machine Both media carry polishing compound far better than they carry it dry — add wax or dry polishing cream in small, regular doses rather than one large charge. In rotary barrel tumbling, walnut shell at 50%–60% barrel fill is the usual starting point for cut-and-gloss stages, while corncob excels in the final gloss stage. For a worked example of stage-by-stage recipes, see our bamboo tumbling machine operation guide, and browse our full dry finishing media and finishing compounds ranges. 6. Selection Checklist by Application Acetate eyewear frames: walnut shell (24#–36#) with polishing wax to remove tool marks, then corncob (30#–40#) for the final gloss. Jewelry and watch parts: corncob extra fine with a touch of luster compound; avoid coarse walnut on delicate clasps and pins. Brass / aluminum hardware: walnut shell (12#–20#) to clear tarnish and burrs; corncob afterward if a softer cosmetic gloss is wanted. Threaded or tolerance-critical parts: corncob only, or walnut at fine grades and short cycles — check dimensions after the first trial run. Drying after wet vibratory finishing: corncob, always — its absorbency outperforms walnut for water and emulsion removal. 7. Run a Simple Media Trial Before Committing Media choice is ultimately empirical. Run a 2–4 hour trial with a marked sample batch: weigh the parts before and after, photograph surfaces under the same light, and check critical dimensions. If the surface is clean but not bright, move from corncob toward walnut (or add compound). If edges are rounding or dimensions are drifting, move toward corncob or a finer grade. Our rotary barrel tumbling machines work with both media families, and our team can recommend a starting recipe for your material and finish target. Not sure which media suits your parts? Send your part material, size, current surface condition, and target finish. Our finishing team will recommend the media grade, compound, and cycle to test first. Contact Our Finishing Team Official website: www.surface-polish.com  |  Support email: info@surface-polish.com

Single-Station Eco Manual Polishing Machine: Operation Manual, Maintenance Schedule & Finishing Recipes Model Series: SPM-ECO-1000 • Eco-Friendly Dust-Controlled Buffing Workstation • Optical & Hardware Edition The Jintaijin SPM-ECO-1000 single-station eco manual polishing machine is an eco-friendly precision buffing workstation engineered for high-gloss finishing of cellulose acetate eyewear, optical parts, jewelry, watch cases, and fine hardware. A 1.5 kW stepless VFD spindle (0–3,600 RPM), high-velocity negative-pressure dust extraction (1,200–1,500 m³/h), 5–10 µm multi-pocket polyester filtration, and a 15 L slide-out recovery drawer deliver superior surface gloss with zero airborne dust. This manual covers product specifications, mechanical architecture, essential safety regulations, installation and pre-commissioning, the full standard operating procedure (SOP), dust filtration and shaker operation, preventive maintenance, troubleshooting, and factory spare parts. If you are comparing equipment options first, review our finishing machine collection or the wider grinding & finishing machine range. MSDS Download (English, original document). Material Safety Data Sheet for Jintaijin resin abrasive polishing media — provided exactly as issued, unmodified. Download MSDS (EN) — PDF Equipment overview & capability. The SPM-ECO-1000 integrates high-torque buffing spindle mechanics with a self-contained dust extraction blower and high-efficiency filtration matrix for industrial surface polishing. Featuring a stepless VFD spindle, negative-pressure suction hood, mechanical dust shaker lever, and a sealed 15-liter recovery drawer, it suits acetate/propionate eyewear frames, optical parts, jewelry, watch cases, and fine hardware finishing. 1. Technical Parameters & Specifications The table below lists the standard engineering configuration of the SPM-ECO-1000 single-station eco manual polishing machine. Technical Parameter Engineering Value / Range Specification Notes Spindle Motor Power 1.5 kW / 2.0 HP (Continuous Duty S1) High-Torque Induction Motor with VFD Inverter Spindle Speed Range 0 – 3,600 RPM (Stepless Regulated) Digital RPM Display & Precision Potentiometer Dial Dust Extraction Blower 0.75 kW (High-Pressure Backward Centrifugal) Airflow Rate: 1,200 – 1,500 m³/h (700 – 880 CFM) Inlet Suction Velocity ≥ 18.0 m/s at Extraction Throat Direct Particle Pull with Zero Ambient Leakage Filtration Rating & Media 5 – 10 µm Needle-Punched Polyester Fabric ≥ 98.5% Dust Separation Rating (Multi-Pocket Array) Dust Collection Capacity 15 Liters Slide-Out Steel Drawer Dual Quick-Release Toggle Clamps & EPDM Seal Buffing Wheel Range Ø150 mm – Ø250 mm (6" – 10" Diameter) Core Arbor Bore: Ø16 mm or Ø25 mm Spindle Shaft Specification Precision Solid Alloy Steel Ø25 mm M16 Left-Hand Reverse Thread; Runout ≤ 0.02 mm Workstation Lighting 24W Shadowless Industrial LED Bar Illuminance ≥ 1,200 Lux at Tabletop Working Plane Power Supply & Voltage 220V 1-Phase / 380V 3-Phase, 50/60 Hz Chassis Grounding Resistance strictly < 4.0 Ω Acoustic Noise Rating ≤ 72 dB(A) at 1.0 m operator distance Compliant with ISO 11202 & OSHA 1910.95 Machine Dimensions / Weight 850 × 750 × 1,350 mm (L×W×H) | 115 kg Heavy-Duty Welded Frame + 4 Leveling Footpads 2. Mechanical Architecture & Subsystem Identification The machine integrates a buffing spindle, negative-pressure extraction, multi-pocket filtration, and a sealed recovery drawer into one dust-controlled workstation. The diagram below identifies all primary structural components and their exact English technical terms. Figure 1: Overall System Architecture, Structural Layout, and Key Component Identification 2.1 Core Subsystem Breakdown # Component Functional Description & Operational Role 1 Precision Spindle Arbor Solid Ø25mm alloy shaft with M16 reverse-thread nut and clamping flanges. 2 Aerodynamic Suction Hood Wide negative-pressure intake hood pulling dust directly behind the wheel. 3 Dust Recovery Drawer 15-liter slide-out steel bin with dual quick-release airtight toggle latches. 4 Multi-Pocket Filter Chamber Houses 4 polyester cloth filter bags (5–10µm) with ≥98.5% separation rating. 5 Polycarbonate Safety Visor Hinged, high-impact transparent shield protecting operator from flying swarf. 6 24W Shadowless LED Lamp Daylight-spectrum LED bar illuminating the polishing contact plane (≥1200 Lux). 7 Control Console Front panel with E-Stop, Power/Suction/Light switches, and VFD RPM dial. 8 Leveling Footpads Four adjustable heavy-duty rubber-cushioned M16 anti-vibration feet. 9 Dust Shaker Lever External side lever linked to internal grid to dislodge filter cake into the drawer. Figure 2: Detail Zoom 1 — Precision Polishing Spindle, Bearing Housing, Flange Clamping, and Reverse-Thread Locking Nut Figure 3: Detail Zoom 2 — Single-Port Aerodynamic Extraction Hood, Dual-Vortex Airflow, and Particle Capture Dynamics Figure 4: Detail Zoom 3 — Multi-Pocket Fabric Filter Matrix, Mechanical Shaker Agitation Grid, and Slide-Out Recovery Drawer Figure 5: Detail Zoom 4 — Industrial Operator Control Console, Electrical Switches, VFD Speed Regulator, and Emergency Stop Interface 3. Essential Safety Regulations & Hazard Controls DANGER — severe mechanical entanglement hazard: NO GLOVES. STRICT PROHIBITION OF GLOVES: NEVER wear gloves (cotton, leather, rubber, or nitrile), loose clothing, neckties, rings, or wrist jewelry during polishing spindle operation. The high-speed rotating spindle and cotton buff will instantly grab textile fibers and drag the operator’s hands into the arbor within milliseconds. Long hair MUST be securely bound in a protective cap. 3.1 Mandatory Personal Protective Equipment (PPE) Eye & Face Protection: ANSI Z87.1 / EN 166 Grade B certified safety goggles or face shield. Respiratory Protection: NIOSH N95 or EN 149 FFP2 particulate respirator for fine dust. Hearing Protection: Industrial earplugs or earmuffs (NRR ≥ 22 dB) during extended shifts. Apparel & Footwear: Snug workwear with elastic cuffs; steel-toe anti-slip safety shoes. 3.2 Combustible Dust & Static Grounding Protocols Grounding: Cellulose acetate, acrylic, and polishing wax generate combustible fine dust. Ensure chassis grounding resistance is strictly < 4.0 Ω to dissipate static charge buildup. Spark Control: NEVER polish spark-producing ferrous metals (steel/iron) without prior complete cleanout of the filtration chamber and dust drawer. 4. Installation & Pre-Commissioning 1. Leveling. Place machine on a level concrete floor. Adjust 4 leveling footpads until the tabletop is level in all axes, then lock jam nuts. 2. Electrical. Connect to dedicated branch circuit (16A breaker for 220V 1-Phase; 10A breaker for 380V 3-Phase). Secure PE ground wire (<4Ω). 3. Rotation. Buffing wheel MUST rotate clockwise downward toward operator. If rotation is reversed on 3-phase units, swap incoming lines L1 and L2. 4. Wheel Mounting. Slide inner flange onto shaft → Mount wheel → Slide outer flange → Hand-thread M16 reverse nut → Tighten firmly with spanner (45–50 N·m). 5. Standard Operating Procedures (SOP) & Finishing Follow this streamlined 4-stage workflow to guarantee repeatable, mirror-grade finishing and ensure maximum operator safety. Figure 6: Standard Operating Procedure (SOP) 4-Stage Operational Workflow & Recommended 4:00 – 6:00 Safe Wheel Contact Arc 5.1 Daily Startup Sequence 1. Power. Turn ON Main Power isolator switch (green indicator illuminates). 2. Suction. Press DUST SUCTION button and verify strong negative air draw at the hood throat. 3. Lighting. Turn ON LED Work Light switch to illuminate the contact plane. 4. Spindle. Press SPINDLE START and dial VFD speed potentiometer to target RPM (2,000–2,400 RPM for acetate; 3,000 RPM for metal). 5.2 Workpiece Contact Arc & Kickback Prevention WARNING — kickback danger & safe contact zone. MANDATORY CONTACT ZONE (4:00 TO 6:00 ARC): Always present the workpiece against the LOWER QUADRANT of the wheel (between 4:00 and 6:00). NEVER polish above the centerline (12:00 to 2:00 zone) — the wheel will violently snatch and throw the workpiece forward (kickback hazard). Maintain light, steady, tangential pressure. 5.3 Eyewear & Precision Hardware 3-Stage Finishing Protocol Process Stage Recommended Wheel Compound Speed Surface Objective Stage 1 (Coarse Cut & Deburr) Spiral cotton / sisal wheel Brown Tripoli compound 2,200–2,400 RPM Removes CNC milling tool marks and burrs. Stage 2 (Smooth & Level) Yellow treated cotton wheel Green Chromium Oxide compound 2,000–2,200 RPM Buffs frame bevels and bridge into a smooth satin finish. Stage 3 (Mirror Finish) Soft unstitched muslin wheel Blue Luster or White Diamond wax 1,800–2,000 RPM Polish with light touch for optical mirror gloss. Compound tip — dedicated wheels per stage. Always use a dedicated buffing wheel per compound grade. A wheel contaminated with coarse Tripoli will transfer swirl marks into the final mirror stage. Rake wheels clean between batches. 5.4 End-of-Shift Shutdown Routine Stop spindle → Run suction for 30s to purge ductwork → Turn OFF suction, light, and power → Pump dust shaker lever 6–8 times into drawer. 6. Dust Filtration, Shaker Operation & Recovery 1. Recovery Drawer — empty daily. Turn OFF machine. Release dual quick-latches, slide 15L drawer out, empty swarf into waste/recycling bin, wipe EPDM gasket clean, and clamp latches airtight. 2. Shaker Agitation — every 4 hours. With suction fan completely OFF, grasp external side shaker lever and pump vigorously 6–10 times. Internal grid shakes caked dust down into the drawer. 3. Swarf Recovery — precious metal reclamation. The sealed collection drawer enables 100% dry reclamation of gold, silver, brass, and titanium polishing swarf without slurry contamination. 7. Preventive Maintenance & Troubleshooting 7.1 Preventive Maintenance Schedule Maintenance Frequency Mandatory Inspection & Service Procedures Daily (Every Shift) Empty 15L recovery drawer; clean PC visor; pump filter shaker 6–8 times; check wheel wear. Weekly (40 Hours) Inspect spindle arbor runout; check drive belt tension; inspect EPDM drawer gasket seal. Monthly (160 Hours) Inspect filter bags for tears or caking; verify ground bond (<4.0 Ω); check electrical terminals. Semi-Annually (1,000 Hours) Lubricate spindle bearings with 3–5g high-speed grease (Mobil Polyrex EM); check VFD. Annually (2,000 Hours) Replace complete set of multi-pocket filter bags (SPM-FLT-1004); inspect motor dynamic balance. 7.2 Comprehensive Troubleshooting Matrix Fault Symptom Probable Root Causes Corrective Action & Resolution Machine will not power ON Main breaker tripped; E-Stop locked down; blown fuse. Reset breaker; rotate E-Stop clockwise to release; check fuse. Motor hums but will not spin Phase loss on power line; VFD fault; arbor jam. Verify incoming line voltages; check VFD code; clear arbor. Excessive machine vibration Unbalanced buffing wheel; loose M16 lock nut. Dress or replace buffing wheel; tighten M16 nut to 45 N·m. Weak suction airflow at hood Filter bags caked; drawer unlatched; duct clog. Pump shaker lever 10 times; clamp drawer tight; clear duct. Workpiece burning (Acetate) RPM too high; excessive pressure; dry buffing wheel. Reduce speed to 2,000–2,400 RPM; use light touch; apply wax. Swirl marks / haze on surface Wheel contaminated with coarse compound/grit. Rake wheel clean; use dedicated buffing wheel per compound. Acoustic squeal / grinding noise Dry spindle bearings; loose drive belt rubbing frame. Grease bearings with Mobil Polyrex EM; adjust belt tension. 8. Spare Parts & Factory Service Contact 8.1 Genuine Factory Spare Parts Catalog Part Description & Specifications Factory Part No. Application & Replacement Notes Multi-Pocket Polyester Filter Bag Set (4 Pockets, 5–10µm) SPM-FLT-1004 Replace every 12–18 months depending on duty cycle Polycarbonate Safety Visor Shield (3mm High-Impact PC) SPM-SHD-PC01 Pre-drilled mounting holes with hinge hardware NSK High-Speed Spindle Deep Groove Ball Bearings (Pair) BRG-6205-2RS Pre-greased, double rubber sealed (25×52×15 mm) Over-Center Toggle Clamps with Rubber Spindle Pad CLP-TGL-GH403 Heavy-duty zinc-plated steel for recovery drawer M16 Left-Hand Reverse Thread Hex Nut & Clamping Flanges NUT-M16-LH02 Precision balanced alloy steel hardware set Mushroom Head Twist-to-Reset Emergency Stop Pushbutton SW-ESTOP-XB2 Standard 22mm panel mount, 1NC contact block 24W Industrial Shadowless Daylight LED Tube Luminaire LED-T8-24W-6.5K 6500K Color Temperature, IP54 dust resistant EPDM Foam Airtight Recovery Drawer Sealing Gasket GSK-EPDM-1505 Self-adhesive oil and wax resistant sponge rubber 8.2 Manufacturer Warranty & Official Contact The SPM-ECO-1000 is backed by a 12-Month Manufacturer Warranty covering motor, blower, VFD, and structural frame under normal industrial operation. For technical assistance, custom buffing process development, replacement wheels, or spare parts inquiries, contact our engineering support team. We also offer OEM/ODM customization and consumables supply for the full single-station polishing machine range — browse our finishing compounds and consumables categories for stage-matched waxes, compounds, and buffing wheels. Need a dust-controlled buffing workstation for your parts? Send your part material, size, current surface condition, and target finish. Our finishing team can recommend the right machine, wheels, compound, and test process. Contact Our Finishing Team Jintaijin POLISH MACHINERY CO., LTD. • Official website: www.surface-polish.com  |  Support email: info@surface-polish.com  |  ISO 9001:2015 & CE Certified

Double-Deck Bamboo Tumbling Machine: Standard Operating Procedure, Control Guide & Finishing Recipes Model Series: SP-TB4 / SP-TB8 • Precision Dry Tumbling System • Official operation manual The SP-TB Series double-deck bamboo tumbling machine is a precision dry tumbling system designed for high-gloss finishing of premium eyewear frames (acetate, propionate), fine hardware, jewelry, and luxury plastic or wood components. Its octagonal, seasoned bamboo barrels provide natural thermal buffering, gentle wax absorption, and a soft cascading action that delivers mirror-like surfaces without edge distortion. This manual covers machine structure, control panel operation, the full 6-step standard operating procedure (SOP), proven dry tumbling recipes, preventive maintenance, and quick troubleshooting. If you are comparing equipment options first, review our rotary barrel tumbling machines range or the wider finishing machine collection. Equipment overview & capability. The two-tier vertical architecture saves floor space while doubling batch output. Each barrel is built from aged natural bamboo staves with stainless steel ventilation screens, and the drive system is protected by a full-height yellow wire mesh guard. The machine is suited to acetate/propionate eyewear frames, fine hardware, jewelry, and luxury plastic/wood components. 1. Technical Parameters & Configuration The table below lists the standard engineering configuration of the SP-TB4 (4-barrel) and SP-TB8 (8-barrel) models. Technical Parameter Engineering Specification / Configuration Structure / Barrels Double-Deck (2 Tiers), 4 or 8 Octagonal Bamboo Barrels Barrel Material Aged Natural Bamboo Staves with SS Ventilation Filter Screens Main Motor / Power 2.2 kW / 3.0 HP High-Torque Heavy-Duty Motor (380V 3-Phase / 220V 1-Phase) Tumbling Speed 28 – 35 RPM (Optimized Gravity Cascade Angle: 45°–50°) Control System Digital Microprocessor Timer (0–99.9 h/m), Start, Stop, JOG Inching, Reset Safety Enclosure Full-Height Industrial Yellow Wire Mesh Guard Enclosure Discharge System Heavy-Duty Middle Galvanized Pull-Out Receiving Hopper Tray Official Support Website: www.surface-polish.com | Email: info@surface-polish.com 2. Machine Structure & Component Nomenclature The machine layout features a space-saving two-tier vertical architecture. The diagram and table below identify all primary structural components and their exact English technical terms. Figure 1: Machine Structural Layout & Subsystem Nomenclature # Component Functional Description & Operational Role 1 Bamboo Tumblers Dual-deck octagonal barrels (#3, #4 upper; #7, #8 lower) for gentle cascading dry polishing. 2 Clamping Bars & Latches Heavy-duty steel compression bars with quick-acting toggle clamps to secure hatch doors. 3 Ventilation Mesh Screens Perforated stainless steel screens to dissipate internal frictional heat and vent micro-dust. 4 Receiving Hopper Drawer Middle heavy-gauge galvanized collection tray for clean, rapid workpiece/media discharge. 5 Structural Steel Chassis Rigid, vibration-damped welded steel frame supporting dual-tier drive loads. 6 Yellow Safety Mesh Enclosure Full-height yellow wire mesh cage isolating transmission belts, pulleys, and drive chains. 7 Electric Control Cabinet Dust-proof electrical enclosure housing the pushbutton station, safety locks, and LED timer. 3. Control Panel & Operator Interface The front-mounted control station allows precise cycle management, automated timed shutoff, and micro-positioning (JOG) for loading and unloading. The digital timer automatically stops the machine when the programmed cycle is complete. Figure 2: Electrical Control Cabinet Interface & Button Layout Control Element Hardware Type / Color Operating Logic & Standard Action Power Lamp Red Pilot Lamp (Top) Illuminates continuously when the 3-phase/single-phase main power supply is energized. Start Button Green Pushbutton Latches the main magnetic contactor to start continuous automatic tumbling cycle. Stop Button Red Pushbutton Immediately de-energizes the drive motor and halts all barrel rotation. JOG / Inching Yellow Pushbutton Momentary run: rotates barrels only while pressed. Used to align doors for loading/unloading. Timer Reset Blue Pushbutton Resets the digital timer accumulator back to zero (00:00) for a new cycle run. Digital LED Timer Microprocessor Controller Digital display with +/- setting buttons. Automatically shuts down the machine upon cycle completion. CAUTION — JOG (inching) safety rule. Always use the yellow JOG button to rotate barrel doors into position. NEVER attempt to rotate barrels by hand when the motor is stopped or energized, as residual torque may cause pinch hazards. 4. Standard Operating Procedure (6-Step SOP) Follow this streamlined 6-step workflow to guarantee repeatable, mirror-grade polishing and ensure maximum operator safety. Figure 3: Standard Operating Procedure (6-Step Dry Tumbling Workflow) Step 1: Pre-Start Inspection & JOG Positioning. Verify the yellow safety cage is secured. Turn on the main isolator. Press the yellow JOG button intermittently until the target barrel door faces vertically upward (12 o’clock position). Step 2: Load Polishing Media & Workpieces. Release the red toggle latches, remove clamping bars, and open the hatch. Fill the barrel to 50%–60% total volume with walnut shells or corncobs. Add workpieces at a strict 3:1 to 4:1 media-to-workpiece ratio. Step 3: Apply Polishing Wax / Rolling Cream. Distribute specialized polishing wax or rolling oil evenly across the media (15–30 g per batch). Ensure the ventilation screens are clean and unclogged. Step 4: Secure Clamping Bars & Latches. Reinstall the barrel hatch door. Position the steel clamping bars and engage the red toggle clamps until firmly locked. Verify zero clearance around the door gasket. Step 5: Program Digital Timer & Press START. Press the blue TIMER RESET button. Set the desired cycle duration on the digital timer (e.g. 12.0 hours). Press the green START button. The machine runs continuously and auto-stops upon completion. Step 6: Discharge & Workpiece Separation. Slide the galvanized receiving hopper drawer directly under the target barrel. Use the JOG button to rotate the barrel door downward (6 o’clock position). Release the latches, open the hatch, and discharge the contents into the hopper for screening. 5. Dry Tumbling Process Recipes & Media Matrix Dry tumbling relies on progressive multi-stage micro-cutting and buffing. Use the proven recipe chart below for acetate eyewear, luxury plastics, and precision metals. Cycle times are typical starting ranges and should be confirmed with sample parts. Process Stage Recommended Media Polishing Compound Cycle Time Surface Objective 1. Rough Cutting Coarse Walnut Shell (16#–20#) Rough Cut Wax / Gray Paste 8 – 14 Hours Removes CNC milling marks, burrs, and parting lines. 2. Medium Smoothing Medium Walnut Shell (24#–36#) Medium Polish Cream / Brown Wax 10 – 16 Hours Smooths micro-scratches, creates uniform satin finish. 3. Fine Glossing Fine Corncob (20#–40#) / Bamboo Pegs Fine Buffing Oil / White Wax 12 – 18 Hours Enhances surface depth, semi-bright luster, prepares for mirror finish. 4. High Mirror Luster Micro Corncob (40#–60#) / Hard Pegs Mirror Finish Glaze / Blue-Green Wax 14 – 24 Hours Produces flawless, ultra-deep optical clarity & mirror reflection. Pro tip — tumbling volume & density control. Optimal tumbling efficiency occurs at 50%–60% total barrel fill. Never underfill (below 40%, risks severe impact damage) or overfill (above 70%, prevents cascading action and causes matte dead spots). Media and compound selection is the largest variable in dry tumbling results. Browse our dry finishing media range for walnut shell and corncob grades, or review finishing compounds for stage-matched waxes and glazes. 6. Preventive Maintenance & Quick Troubleshooting 6.1 Routine Maintenance Schedule Daily check: inspect door toggle clamps and rubber gaskets for wear. Clear accumulated dust from ventilation mesh screens using a soft brush or shop vacuum. Weekly check: check drive belt tension inside the yellow mesh cage (approx. 10–12 mm deflection under firm thumb pressure). Inspect chain lubrication. Monthly service: apply NLGI #2 lithium grease to all pillow block bearings via grease nipples. Inspect bamboo staves for tightness; tighten mounting bolts if loose. 6.2 Quick Troubleshooting Matrix Fault Symptom Probable Root Cause Corrective Action / Solution Machine fails to start when pressing START Main power off / emergency halt engaged / timer not set / fuse blown Check red power lamp, release stop button, reset timer, check supply breaker. JOG button works but START does not latch Timer timed out / contactor auxiliary contact fault Press blue Timer Reset button; inspect contactor wiring inside control box. Excessive noise or vibration during run Worn pillow block bearing / loose drive chain / unbalanced load Lubricate or replace bearings, adjust chain tensioner, ensure even media filling. Media dust leaking during operation Worn hatch sealing gasket / toggle clamps not fully locked Inspect and replace silicone gasket; adjust clamping bar latch tension. Workpieces have uneven or poor luster Improper media ratio / insufficient wax / clogged mesh screens Adjust media-to-part ratio toward 4:1; clean ventilation screens to prevent overheating. 7. Technical Support & Custom Process Development For technical assistance, custom tumbling process development, replacement barrels, or spare parts inquiries, contact our engineering support team. We also offer OEM/ODM customization, polishing compounds and media supply, and wear parts for the full SP-TB series. Need a custom dry tumbling process for your parts? Send your part material, size, current surface condition, and target finish. Our finishing team can recommend the right machine, media, compound, and test process. Contact Our Finishing Team Official website: www.surface-polish.com  |  Support email: info@surface-polish.com

How to Choose Media Size for Small Holes, Slots and Internal Cavities How to Choose Media Size for Small Holes, Slots and Internal Cavities Short answer: choose the smallest media that reaches the required feature and can still be separated reliably. A smaller chip may improve access, but it can also lodge in a hole, pass through a slot, slow separation or change the contact intensity. The correct size is therefore a geometry, defect, machine and inspection decision—not a simple “smaller is better” rule. Important: confirm media access and separation on representative parts. A catalog size is not proof that a particular shape will pass through your feature without becoming trapped. 1. Map the feature before selecting media Record the smallest opening, slot width, cavity depth and passage length. Also mark threads, sealing faces, cosmetic surfaces and edges that must not be over-rounded. The critical dimension is often not the nominal hole diameter: an angled entry, burr, cross-hole or blind cavity can reduce the usable passage. Through holes: check entry and exit burrs, cross-sections and the chance of a chip passing through and becoming trapped elsewhere.Slots: compare the shortest slot dimension with the media's smallest cross-section and orientation.Blind cavities: check whether media can enter, circulate and leave without packing at the bottom.Internal channels: confirm that the process objective is reachable; surface contact inside a channel may be uneven. 2. Use a fit-and-function screen, not only a size label QuestionWhy it mattersTrial check Can the media enter?A large or poorly oriented shape may never reach the burr.Mark entry and exit; inspect after a short cycle. Can the media leave?Trapped chips create rework, contamination and customer risk.Count retained pieces after separation and washing. Can it protect the edge?Too small or too sharp a contact can increase edge rounding.Measure edge radius and critical dimensions. Media shape changes the effective cross-section. Cylinders, triangles, angle-cut shapes and plastic forms do not enter the same feature in the same way. Select a shape and size together, then check the machine's circulation and separation method. 3. Balance access with lodging and separation Reducing media size may improve access but can make separation slower, especially when the workpiece has many small openings or when the media approaches the feature size. Review the machine's screen, magnetic, flow or vibration separation method before approving a fine media grade. The ceramic versus plastic media guide explains why media family and shape must be considered with geometry. Do not rely on visual shake-out alone. Use a defined retention check, such as a counted sample, flushing step or controlled inspection of cavities. The acceptance method should match the part's risk and customer requirements. 4. Match size to the incoming defect and target finish A small media chip may reach a cavity but lack the mass or cutting action needed to remove a heavy burr. Conversely, a large aggressive media can remove material quickly on an exposed edge while missing the internal feature. Separate the objectives: internal burr removal, surface smoothing, edge radiusing and final polishing may require different stages or machine concepts. For delicate or high-value parts, compare loose bulk finishing with a process that holds the workpiece, such as drag or stream finishing. The machine choice should follow the geometry and damage risk, not the media label alone. 5. A repeatable media-size trial Measure and record the smallest opening, depth and passage length.Select two candidate shapes and two sizes that can be separated by the available equipment.Run a short access trial, then inspect every critical cavity for retained media.Measure burr removal, edge radius, roughness or visual finish as specified.Run the best candidate again with a fresh sample to confirm repeatability.Document the media, machine, load, compound/water, cycle time and separation method. Use the mass-finishing sample trial record to document the size decision and release criteria. For broader machine capacity choices, see the bowl and tub selection guide. Buyer checklistSmallest opening, slot width, cavity depth and passage lengthIncoming burr height and target edge radiusMaterial, hardness, critical dimensions and cosmetic facesCandidate media shape, size and separation methodMachine type, load ratio, compound/water and cycle timeRetention acceptance method and documented release criteria Need help selecting media for internal features?Send the part drawing or photos, smallest passage, incoming burr and target finish. We can help define an access, separation and inspection trial before equipment or media are finalized.Contact SurfacePolish for a process review This guide is a process-selection framework. Final media size, shape and cycle must be confirmed on representative parts.