Guide posts and bushings help a die set close on a repeatable path, but they should not be used to force a misaligned press or platen into position. Scoring, uneven polish, heat and debris can indicate lubrication loss, side loading, mounting error or wear. Replacing only one bushing may leave the cause unchanged.
This guide focuses on the removable die-set relationship and complements the broader platen inspection. Lock out the machine, block gravity movement and follow the tooling supplier procedure. Acceptable clearance and lubricant are design-specific.
Decision matrix
| Inspection point | Evidence | Interpretation |
|---|---|---|
| Guide surfaces | Scoring, polish pattern, corrosion and debris | Shows contact and contamination history |
| Fit/play | Measured movement at defined position and direction | Compares guide pairs and approved limits |
| Die mounting | Keys, pilots, clamps and seating surfaces | Separates mounting error from guide wear |
| Platen travel | Parallelism and side load through stroke | Finds machine-level cause |
| First article | Form depth, flange, cut/crease and ejection pattern | Connects alignment to product quality |
Preserve wear and product evidence
Collect first articles showing the fault and mark orientation in the die. Record whether variation follows one cavity, one guide corner, machine warm-up or load. Photograph guide-post polish, scoring and lubricant condition before cleaning.
Uneven product depth does not prove guide wear. Tool seating, platen parallelism, material, pressure and ejector condition can produce similar patterns. Use the linked guide to separate machine structure from the die set.
Inspect posts, bushings and lubrication
With the die safely removed or opened under the approved support method, clean inspection areas without abrasive damage. Check each post for scoring, galling, corrosion and steps; inspect bushing edges, retainers, lubrication grooves and seals where fitted.
Identify the specified lubricant and delivery method. Do not mix grease or add a heavy lubricant to hide play. Contamination embedded in a bushing can damage a new post, so inspect both members as a pair.
Measure fit with defined datums
Use the tooling maker’s method to measure guide movement at a controlled open position and direction. Compare all corners and repeat the reading. Record instrument, setup, temperature and whether the die is loaded. A single hand-feel judgment cannot support replacement.
If one guide binds while another shows play, check post parallelism and die-plate distortion. Never lap, grind or hammer precision guide surfaces at the machine without an approved repair plan.
Verify die seating and platen relationship
Inspect mounting faces, keys, pilots, clamps and fasteners for debris or witness marks. Seat the upper and lower tooling against the specified datums without using guide posts to pull it into alignment. Confirm platen travel and parallelism before tightening a suspect die.
Jog through the permitted stroke with suitable clearance evidence and no material. Stop at any tight point. A guide that moves freely near open position can bind near closure when the platen or die plates are not parallel.
Approve repair through first articles
Replace posts and bushings in the supplier-approved combination, including matched components where required. Restore lubrication and retainers, then check free travel and contact before applying process load. Increase forming force and speed only through the machine setup method.
Inspect first articles by cavity and orientation for forming depth, flange, cut/crease, marks and ejection. Record parts, measurements and samples. Send HANNAI the tooling drawing, guide labels and mapped defects for a repair or replacement review.
Related machine and guide
Review the paper plate and box forming equipment for machine context, then use the platen parallelism and guide-post wear guide for the adjacent check. Browse all Buyer Guides when building a wider project checklist.
Frequently asked questions
Does one loose bushing justify replacing only that bushing?
Not automatically; inspect the mating post, alignment, lubrication and matched-component requirements.
Can guide posts pull a misaligned die into position?
They should guide an aligned die set, not correct mounting or platen error.
Is hand-feel enough to judge clearance?
No. Use the tooling maker method and record repeated measurements.
What confirms a successful repair?
Free controlled travel plus stable cavity-mapped first articles under the approved setup.
Review your machine configuration with HANNAI
Send the machine model, project reference, component labels, drawings, photos and a description of the required result. We will clarify which details must be confirmed before a quotation or technical recommendation.